{
    "mode": "perldoc",
    "parameter": "POSIX",
    "section": "",
    "url": "https://www.chedong.com/phpMan.php/perldoc/POSIX/json",
    "generated": "2026-10-04T13:22:53Z",
    "synopsis": "use POSIX ();\nuse POSIX qw(setsid);\nuse POSIX qw(:errnoh :fcntlh);\nprintf \"EINTR is %d\\n\", EINTR;\nmy $sessid = POSIX::setsid();\nmy $fd = POSIX::open($path, OCREAT|OEXCL|OWRONLY, 0644);\n# note: that's a filedescriptor, *NOT* a filehandle",
    "sections": {
        "NAME": {
            "content": "POSIX - Perl interface to IEEE Std 1003.1\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "use POSIX ();\nuse POSIX qw(setsid);\nuse POSIX qw(:errnoh :fcntlh);\n\nprintf \"EINTR is %d\\n\", EINTR;\n\nmy $sessid = POSIX::setsid();\n\nmy $fd = POSIX::open($path, OCREAT|OEXCL|OWRONLY, 0644);\n# note: that's a filedescriptor, *NOT* a filehandle\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "The POSIX module permits you to access all (or nearly all) the standard POSIX 1003.1\nidentifiers. Many of these identifiers have been given Perl-ish interfaces.\n\nThis document gives a condensed list of the features available in the POSIX module. Consult your\noperating system's manpages for general information on most features. Consult perlfunc for\nfunctions which are noted as being identical or almost identical to Perl's builtin functions.\n\nThe first section describes POSIX functions from the 1003.1 specification. The second section\ndescribes some classes for signal objects, TTY objects, and other miscellaneous objects. The\nremaining sections list various constants and macros in an organization which roughly follows\nIEEE Std 1003.1b-1993.\n\nThe notation \"[C99]\" indicates functions that were added in the ISO/IEC 9899:1999 version of the\nC language standard. Some may not be available on your system if it adheres to an earlier\nstandard. Attempts to use any missing one will result in a fatal runtime error message.\n",
            "subsections": []
        },
        "CAVEATS": {
            "content": "*Everything is exported by default* (with a handful of exceptions). This is an unfortunate\nbackwards compatibility feature and its use is strongly discouraged. You should either prevent\nthe exporting (by saying \"use POSIX ();\", as usual) and then use fully qualified names (e.g.\n\"POSIX::SEEKEND\"), or give an explicit import list. If you do neither and opt for the default\n(as in \"use POSIX;\"), you will import *hundreds and hundreds* of symbols into your namespace.\n\nA few functions are not implemented because they are C specific. If you attempt to call these,\nthey will print a message telling you that they aren't implemented, and suggest using the Perl\nequivalent, should one exist. For example, trying to access the setjmp() call will elicit the\nmessage \"\"setjmp() is C-specific: use eval {} instead\"\".\n\nFurthermore, some evil vendors will claim 1003.1 compliance, but in fact are not so: they will\nnot pass the PCTS (POSIX Compliance Test Suites). For example, one vendor may not define\n\"EDEADLK\", or the semantics of the errno values set by open(2) might not be quite right. Perl\ndoes not attempt to verify POSIX compliance. That means you can currently successfully say \"use\nPOSIX\", and then later in your program you find that your vendor has been lax and there's no\nusable \"ICANON\" macro after all. This could be construed to be a bug.\n",
            "subsections": []
        },
        "FUNCTIONS": {
            "content": "\"exit\" This is identical to the C function exit(). It exits the program immediately which\nmeans among other things buffered I/O is not flushed.\n\nNote that when using threads and in Linux this is not a good way to exit a thread\nbecause in Linux processes and threads are kind of the same thing (Note: while this is\nthe situation in early 2003 there are projects under way to have threads with more\nPOSIXly semantics in Linux). If you want not to return from a thread, detach the thread.\n\n\"abort\" This is identical to the C function abort(). It terminates the process with a \"SIGABRT\"\nsignal unless caught by a signal handler or if the handler does not return normally (it\ne.g. does a \"longjmp\").\n\n\"abs\"   This is identical to Perl's builtin abs() function, returning the absolute value of its\nnumerical argument (except that POSIX::abs() must be provided an explicit value (rather\nthan relying on an implicit $):\n\n$absolutevalue = POSIX::abs(42);   # good\n\n$absolutevalue = POSIX::abs();     # throws exception\n\n\"access\"\nDetermines the accessibility of a file.\n\nif( POSIX::access( \"/\", &POSIX::ROK ) ){\nprint \"have read permission\\n\";\n}\n\nReturns \"undef\" on failure. Note: do not use access() for security purposes. Between the\naccess() call and the operation you are preparing for the permissions might change: a\nclassic *race condition*.\n\n\"acos\"  This is identical to the C function acos(), returning the arcus cosine of its numerical\nargument. See also Math::Trig.\n\n\"acosh\" This is identical to the C function acosh(), returning the hyperbolic arcus cosine of\nits numerical argument [C99]. See also Math::Trig. Added in Perl v5.22.\n\n\"alarm\" This is identical to Perl's builtin alarm() function, either for arming or disarming the\n\"SIGARLM\" timer, except that POSIX::alarm() must be provided an explicit value (rather\nthan relying on an implicit $):\n\nPOSIX::alarm(3)     # good\n\nPOSIX::alarm()      # throws exception\n\n\"asctime\"\nThis is identical to the C function asctime(). It returns a string of the form\n\n\"Fri Jun  2 18:22:13 2000\\n\\0\"\n\nand it is called thusly\n\n$asctime = asctime($sec, $min, $hour, $mday, $mon,\n$year, $wday, $yday, $isdst);\n\nThe $mon is zero-based: January equals 0. The $year is 1900-based: 2001 equals 101.\n$wday and $yday default to zero (and are usually ignored anyway), and $isdst defaults to\n-1.\n\nNote the result is always in English. Use \"strftime\" instead to get a result suitable\nfor the current locale. That function's %c format yields the locale's preferred\nrepresentation.\n\n\"asin\"  This is identical to the C function asin(), returning the arcus sine of its numerical\nargument. See also Math::Trig.\n\n\"asinh\" This is identical to the C function asinh(), returning the hyperbolic arcus sine of its\nnumerical argument [C99]. See also Math::Trig. Added in Perl v5.22.\n\n\"assert\"\nUnimplemented, but you can use \"die\" in perlfunc and the Carp module to achieve similar\nthings.\n\n\"atan\"  This is identical to the C function atan(), returning the arcus tangent of its numerical\nargument. See also Math::Trig.\n\n\"atanh\" This is identical to the C function atanh(), returning the hyperbolic arcus tangent of\nits numerical argument [C99]. See also Math::Trig. Added in Perl v5.22.\n\n\"atan2\" This is identical to Perl's builtin atan2() function, returning the arcus tangent\ndefined by its two numerical arguments, the *y* coordinate and the *x* coordinate. See\nalso Math::Trig.\n\n\"atexit\"\nNot implemented. atexit() is C-specific: use \"END {}\" instead, see perlmod.\n\n\"atof\"  Not implemented. atof() is C-specific. Perl converts strings to numbers transparently.\nIf you need to force a scalar to a number, add a zero to it.\n\n\"atoi\"  Not implemented. atoi() is C-specific. Perl converts strings to numbers transparently.\nIf you need to force a scalar to a number, add a zero to it. If you need to have just\nthe integer part, see \"int\" in perlfunc.\n\n\"atol\"  Not implemented. atol() is C-specific. Perl converts strings to numbers transparently.\nIf you need to force a scalar to a number, add a zero to it. If you need to have just\nthe integer part, see \"int\" in perlfunc.\n\n\"bsearch\"\nbsearch() not supplied. For doing binary search on wordlists, see Search::Dict.\n\n\"calloc\"\nNot implemented. calloc() is C-specific. Perl does memory management transparently.\n\n\"cbrt\"  The cube root [C99]. Added in Perl v5.22.\n\n\"ceil\"  This is identical to the C function ceil(), returning the smallest integer value greater\nthan or equal to the given numerical argument.\n\n\"chdir\" This is identical to Perl's builtin chdir() function, allowing one to change the working\n(default) directory -- see \"chdir\" in perlfunc -- with the exception that POSIX::chdir()\nmust be provided an explicit value (rather than relying on an implicit $):\n\n$rv = POSIX::chdir('path/to/dir');      # good\n\n$rv = POSIX::chdir();                   # throws exception\n\n\"chmod\" This is identical to Perl's builtin chmod() function, allowing one to change file and\ndirectory permissions -- see \"chmod\" in perlfunc -- with the exception that\nPOSIX::chmod() can only change one file at a time (rather than a list of files):\n\n$c = chmod 0664, $file1, $file2;          # good\n\n$c = POSIX::chmod 0664, $file1;           # throws exception\n\n$c = POSIX::chmod 0664, $file1, $file2;   # throws exception\n\nAs with the built-in chmod(), $file may be a filename or a file handle.\n\n\"chown\" This is identical to Perl's builtin chown() function, allowing one to change file and\ndirectory owners and groups, see \"chown\" in perlfunc.\n\n\"clearerr\"\nNot implemented. Use the method IO::Handle::clearerr() instead, to reset the error state\n(if any) and EOF state (if any) of the given stream.\n\n\"clock\" This is identical to the C function clock(), returning the amount of spent processor\ntime in microseconds.\n\n\"close\" Close the file. This uses file descriptors such as those obtained by calling\n\"POSIX::open\".\n\n$fd = POSIX::open( \"foo\", &POSIX::ORDONLY );\nPOSIX::close( $fd );\n\nReturns \"undef\" on failure.\n\nSee also \"close\" in perlfunc.\n\n\"closedir\"\nThis is identical to Perl's builtin closedir() function for closing a directory handle,\nsee \"closedir\" in perlfunc.\n\n\"cos\"   This is identical to Perl's builtin cos() function, for returning the cosine of its\nnumerical argument, see \"cos\" in perlfunc. See also Math::Trig.\n\n\"cosh\"  This is identical to the C function cosh(), for returning the hyperbolic cosine of its\nnumeric argument. See also Math::Trig.\n\n\"copysign\"\nReturns \"x\" but with the sign of \"y\" [C99]. Added in Perl v5.22.\n\n$xwithsignofy = POSIX::copysign($x, $y);\n\nSee also \"signbit\".\n\n\"creat\" Create a new file. This returns a file descriptor like the ones returned by\n\"POSIX::open\". Use \"POSIX::close\" to close the file.\n\n$fd = POSIX::creat( \"foo\", 0611 );\nPOSIX::close( $fd );\n\nSee also \"sysopen\" in perlfunc and its \"OCREAT\" flag.\n\n\"ctermid\"\nGenerates the path name for the controlling terminal.\n\n$path = POSIX::ctermid();\n\n\"ctime\" This is identical to the C function ctime() and equivalent to \"asctime(localtime(...))\",\nsee \"asctime\" and \"localtime\".\n\n\"cuserid\" [POSIX.1-1988]\nGet the login name of the owner of the current process.\n\n$name = POSIX::cuserid();\n\nNote: this function has not been specified by POSIX since 1990 and is included only for\nbackwards compatibility. New code should use getlogin() instead.\n\n\"difftime\"\nThis is identical to the C function difftime(), for returning the time difference (in\nseconds) between two times (as returned by time()), see \"time\".\n\n\"div\"   Not implemented. div() is C-specific, use \"int\" in perlfunc on the usual \"/\" division\nand the modulus \"%\".\n\n\"dup\"   This is similar to the C function dup(), for duplicating a file descriptor.\n\nThis uses file descriptors such as those obtained by calling \"POSIX::open\".\n\nReturns \"undef\" on failure.\n\n\"dup2\"  This is similar to the C function dup2(), for duplicating a file descriptor to an\nanother known file descriptor.\n\nThis uses file descriptors such as those obtained by calling \"POSIX::open\".\n\nReturns \"undef\" on failure.\n\n\"erf\"   The error function [C99]. Added in Perl v5.22.\n\n\"erfc\"  The complementary error function [C99]. Added in Perl v5.22.\n\n\"errno\" Returns the value of errno.\n\n$errno = POSIX::errno();\n\nThis identical to the numerical values of the $!, see \"$ERRNO\" in perlvar.\n\n\"execl\" Not implemented. execl() is C-specific, see \"exec\" in perlfunc.\n\n\"execle\"\nNot implemented. execle() is C-specific, see \"exec\" in perlfunc.\n\n\"execlp\"\nNot implemented. execlp() is C-specific, see \"exec\" in perlfunc.\n\n\"execv\" Not implemented. execv() is C-specific, see \"exec\" in perlfunc.\n\n\"execve\"\nNot implemented. execve() is C-specific, see \"exec\" in perlfunc.\n\n\"execvp\"\nNot implemented. execvp() is C-specific, see \"exec\" in perlfunc.\n\n\"exit\"  This is identical to Perl's builtin exit() function for exiting the program, see \"exit\"\nin perlfunc.\n\n\"exp\"   This is identical to Perl's builtin exp() function for returning the exponent\n(*e*-based) of the numerical argument, see \"exp\" in perlfunc.\n\n\"expm1\" Equivalent to \"exp(x) - 1\", but more precise for small argument values [C99]. Added in\nPerl v5.22.\n\nSee also \"log1p\".\n\n\"fabs\"  This is identical to Perl's builtin abs() function for returning the absolute value of\nthe numerical argument, see \"abs\" in perlfunc.\n\n\"fclose\"\nNot implemented. Use method IO::Handle::close() instead, or see \"close\" in perlfunc.\n\n\"fcntl\" This is identical to Perl's builtin fcntl() function, see \"fcntl\" in perlfunc.\n\n\"fdopen\"\nNot implemented. Use method IO::Handle::newfromfd() instead, or see \"open\" in\nperlfunc.\n\n\"feof\"  Not implemented. Use method IO::Handle::eof() instead, or see \"eof\" in perlfunc.\n\n\"ferror\"\nNot implemented. Use method IO::Handle::error() instead.\n\n\"fflush\"\nNot implemented. Use method IO::Handle::flush() instead. See also \"\"$OUTPUTAUTOFLUSH\"\nin perlvar\".\n\n\"fgetc\" Not implemented. Use method IO::Handle::getc() instead, or see \"read\" in perlfunc.\n\n\"fgetpos\"\nNot implemented. Use method IO::Seekable::getpos() instead, or see \"seek\" in perlfunc.\n\n\"fgets\" Not implemented. Use method IO::Handle::gets() instead. Similar to <>, also known as\n\"readline\" in perlfunc.\n\n\"fileno\"\nNot implemented. Use method IO::Handle::fileno() instead, or see \"fileno\" in perlfunc.\n\n\"floor\" This is identical to the C function floor(), returning the largest integer value less\nthan or equal to the numerical argument.\n\n\"fdim\"  \"Positive difference\", \"x - y\" if \"x > y\", zero otherwise [C99]. Added in Perl v5.22.\n\n\"fegetround\"\nReturns the current floating point rounding mode, one of\n\nFETONEAREST FETOWARDZERO FEUPWARD FEDOWNWARD\n\n\"FETONEAREST\" is like \"round\", \"FETOWARDZERO\" is like \"trunc\" [C99]. Added in Perl\nv5.22.\n\n\"fesetround\"\nSets the floating point rounding mode, see \"fegetround\" [C99]. Added in Perl v5.22.\n\n\"fma\"   \"Fused multiply-add\", \"x * y + z\", possibly faster (and less lossy) than the explicit\ntwo operations [C99]. Added in Perl v5.22.\n\nmy $fused = POSIX::fma($x, $y, $z);\n\n\"fmax\"  Maximum of \"x\" and \"y\", except when either is \"NaN\", returns the other [C99]. Added in\nPerl v5.22.\n\nmy $max = POSIX::fmax($x, $y);\n\n\"fmin\"  Minimum of \"x\" and \"y\", except when either is \"NaN\", returns the other [C99]. Added in\nPerl v5.22.\n\nmy $min = POSIX::fmin($x, $y);\n\n\"fmod\"  This is identical to the C function fmod().\n\n$r = fmod($x, $y);\n\nIt returns the remainder \"$r = $x - $n*$y\", where \"$n = trunc($x/$y)\". The $r has the\nsame sign as $x and magnitude (absolute value) less than the magnitude of $y.\n\n\"fopen\" Not implemented. Use method IO::File::open() instead, or see \"open\" in perlfunc.\n\n\"fork\"  This is identical to Perl's builtin fork() function for duplicating the current process,\nsee \"fork\" in perlfunc and perlfork if you are in Windows.\n\n\"fpathconf\"\nRetrieves the value of a configurable limit on a file or directory. This uses file\ndescriptors such as those obtained by calling \"POSIX::open\".\n\nThe following will determine the maximum length of the longest allowable pathname on the\nfilesystem which holds /var/foo.\n\n$fd = POSIX::open( \"/var/foo\", &POSIX::ORDONLY );\n$pathmax = POSIX::fpathconf($fd, &POSIX::PCPATHMAX);\n\nReturns \"undef\" on failure.\n\n\"fpclassify\"\nReturns one of\n\nFPNORMAL FPZERO FPSUBNORMAL FPINFINITE FPNAN\n\ntelling the class of the argument [C99]. \"FPINFINITE\" is positive or negative infinity,\n\"FPNAN\" is not-a-number. \"FPSUBNORMAL\" means subnormal numbers (also known as\ndenormals), very small numbers with low precision. \"FPZERO\" is zero. \"FPNORMAL\" is all\nthe rest. Added in Perl v5.22.\n\n\"fprintf\"\nNot implemented. fprintf() is C-specific, see \"printf\" in perlfunc instead.\n\n\"fputc\" Not implemented. fputc() is C-specific, see \"print\" in perlfunc instead.\n\n\"fputs\" Not implemented. fputs() is C-specific, see \"print\" in perlfunc instead.\n\n\"fread\" Not implemented. fread() is C-specific, see \"read\" in perlfunc instead.\n\n\"free\"  Not implemented. free() is C-specific. Perl does memory management transparently.\n\n\"freopen\"\nNot implemented. freopen() is C-specific, see \"open\" in perlfunc instead.\n\n\"frexp\" Return the mantissa and exponent of a floating-point number.\n\n($mantissa, $exponent) = POSIX::frexp( 1.234e56 );\n\n\"fscanf\"\nNot implemented. fscanf() is C-specific, use <> and regular expressions instead.\n\n\"fseek\" Not implemented. Use method IO::Seekable::seek() instead, or see \"seek\" in perlfunc.\n\n\"fsetpos\"\nNot implemented. Use method IO::Seekable::setpos() instead, or seek \"seek\" in perlfunc.\n\n\"fstat\" Get file status. This uses file descriptors such as those obtained by calling\n\"POSIX::open\". The data returned is identical to the data from Perl's builtin \"stat\"\nfunction.\n\n$fd = POSIX::open( \"foo\", &POSIX::ORDONLY );\n@stats = POSIX::fstat( $fd );\n\n\"fsync\" Not implemented. Use method IO::Handle::sync() instead.\n\n\"ftell\" Not implemented. Use method IO::Seekable::tell() instead, or see \"tell\" in perlfunc.\n\n\"fwrite\"\nNot implemented. fwrite() is C-specific, see \"print\" in perlfunc instead.\n\n\"getc\"  This is identical to Perl's builtin getc() function, see \"getc\" in perlfunc.\n\n\"getchar\"\nReturns one character from STDIN. Identical to Perl's getc(), see \"getc\" in perlfunc.\n\n\"getcwd\"\nReturns the name of the current working directory. See also Cwd.\n\n\"getegid\"\nReturns the effective group identifier. Similar to Perl' s builtin variable $(, see\n\"$EGID\" in perlvar.\n\n\"getenv\"\nReturns the value of the specified environment variable. The same information is\navailable through the %ENV array.\n\n\"geteuid\"\nReturns the effective user identifier. Identical to Perl's builtin $> variable, see\n\"$EUID\" in perlvar.\n\n\"getgid\"\nReturns the user's real group identifier. Similar to Perl's builtin variable $), see\n\"$GID\" in perlvar.\n\n\"getgrgid\"\nThis is identical to Perl's builtin getgrgid() function for returning group entries by\ngroup identifiers, see \"getgrgid\" in perlfunc.\n\n\"getgrnam\"\nThis is identical to Perl's builtin getgrnam() function for returning group entries by\ngroup names, see \"getgrnam\" in perlfunc.\n\n\"getgroups\"\nReturns the ids of the user's supplementary groups. Similar to Perl's builtin variable\n$), see \"$GID\" in perlvar.\n\n\"getlogin\"\nThis is identical to Perl's builtin getlogin() function for returning the user name\nassociated with the current session, see \"getlogin\" in perlfunc.\n\n\"getpayload\"\nuse POSIX ':nanpayload';\ngetpayload($var)\n\nReturns the \"NaN\" payload. Added in Perl v5.24.\n\nNote the API instability warning in \"setpayload\".\n\nSee \"nan\" for more discussion about \"NaN\".\n\n\"getpgrp\"\nThis is identical to Perl's builtin getpgrp() function for returning the process group\nidentifier of the current process, see \"getpgrp\" in perlfunc.\n\n\"getpid\"\nReturns the process identifier. Identical to Perl's builtin variable $$, see \"$PID\" in\nperlvar.\n\n\"getppid\"\nThis is identical to Perl's builtin getppid() function for returning the process\nidentifier of the parent process of the current process , see \"getppid\" in perlfunc.\n\n\"getpwnam\"\nThis is identical to Perl's builtin getpwnam() function for returning user entries by\nuser names, see \"getpwnam\" in perlfunc.\n\n\"getpwuid\"\nThis is identical to Perl's builtin getpwuid() function for returning user entries by\nuser identifiers, see \"getpwuid\" in perlfunc.\n\n\"gets\"  Returns one line from \"STDIN\", similar to <>, also known as the readline() function, see\n\"readline\" in perlfunc.\n\nNOTE: if you have C programs that still use gets(), be very afraid. The gets() function\nis a source of endless grief because it has no buffer overrun checks. It should never be\nused. The fgets() function should be preferred instead.\n\n\"getuid\"\nReturns the user's identifier. Identical to Perl's builtin $< variable, see \"$UID\" in\nperlvar.\n\n\"gmtime\"\nThis is identical to Perl's builtin gmtime() function for converting seconds since the\nepoch to a date in Greenwich Mean Time, see \"gmtime\" in perlfunc.\n\n\"hypot\" Equivalent to sqrt(x * x + y * y) except more stable on very large or very small\narguments [C99]. Added in Perl v5.22.\n\n\"ilogb\" Integer binary logarithm [C99]. Added in Perl v5.22.\n\nFor example ilogb(20) is 4, as an integer.\n\nSee also \"logb\".\n\n\"Inf\"   The infinity as a constant:\n\nuse POSIX qw(Inf);\nmy $posinf = +Inf;  # Or just Inf.\nmy $neginf = -Inf;\n\nSee also \"isinf\", and \"fpclassify\".\n\n\"isalnum\"\nThis function has been removed as of Perl v5.24. It was very similar to matching against\n\"qr/ ^ [[:alnum:]]+ $ /x\", which you should convert to use instead. See \"POSIX Character\nClasses\" in perlrecharclass.\n\n\"isalpha\"\nThis function has been removed as of Perl v5.24. It was very similar to matching against\n\"qr/ ^ [[:alpha:]]+ $ /x\", which you should convert to use instead. See \"POSIX Character\nClasses\" in perlrecharclass.\n\n\"isatty\"\nReturns a boolean indicating whether the specified filehandle is connected to a tty.\nSimilar to the \"-t\" operator, see \"-X\" in perlfunc.\n\n\"iscntrl\"\nThis function has been removed as of Perl v5.24. It was very similar to matching against\n\"qr/ ^ [[:cntrl:]]+ $ /x\", which you should convert to use instead. See \"POSIX Character\nClasses\" in perlrecharclass.\n\n\"isdigit\"\nThis function has been removed as of Perl v5.24. It was very similar to matching against\n\"qr/ ^ [[:digit:]]+ $ /x\", which you should convert to use instead. See \"POSIX Character\nClasses\" in perlrecharclass.\n\n\"isfinite\"\nReturns true if the argument is a finite number (that is, not an infinity, or the\nnot-a-number) [C99]. Added in Perl v5.22.\n\nSee also \"isinf\", \"isnan\", and \"fpclassify\".\n\n\"isgraph\"\nThis function has been removed as of Perl v5.24. It was very similar to matching against\n\"qr/ ^ [[:graph:]]+ $ /x\", which you should convert to use instead. See \"POSIX Character\nClasses\" in perlrecharclass.\n\n\"isgreater\"\n(Also \"isgreaterequal\", \"isless\", \"islessequal\", \"islessgreater\", \"isunordered\")\n\nFloating point comparisons which handle the \"NaN\" [C99]. Added in Perl v5.22.\n\n\"isinf\" Returns true if the argument is an infinity (positive or negative) [C99]. Added in Perl\nv5.22.\n\nSee also \"Inf\", \"isnan\", \"isfinite\", and \"fpclassify\".\n\n\"islower\"\nThis function has been removed as of Perl v5.24. It was very similar to matching against\n\"qr/ ^ [[:lower:]]+ $ /x\", which you should convert to use instead. See \"POSIX Character\nClasses\" in perlrecharclass.\n\n\"isnan\" Returns true if the argument is \"NaN\" (not-a-number) [C99]. Added in Perl v5.22.\n\nNote that you can also test for \"\"NaN\"-ness\" with equality operators (\"==\" or \"!=\"), as\nin\n\nprint \"x is not a NaN\\n\" if $x == $x;\n\nsince the \"NaN\" is not equal to anything, including itself.\n\nSee also \"nan\", \"NaN\", \"isinf\", and \"fpclassify\".\n\n\"isnormal\"\nReturns true if the argument is normal (that is, not a subnormal/denormal, and not an\ninfinity, or a not-a-number) [C99]. Added in Perl v5.22.\n\nSee also \"isfinite\", and \"fpclassify\".\n\n\"isprint\"\nThis function has been removed as of Perl v5.24. It was very similar to matching against\n\"qr/ ^ [[:print:]]+ $ /x\", which you should convert to use instead. See \"POSIX Character\nClasses\" in perlrecharclass.\n\n\"ispunct\"\nThis function has been removed as of Perl v5.24. It was very similar to matching against\n\"qr/ ^ [[:punct:]]+ $ /x\", which you should convert to use instead. See \"POSIX Character\nClasses\" in perlrecharclass.\n\n\"issignaling\"\nuse POSIX ':nanpayload';\nissignaling($var, $payload)\n\nReturn true if the argument is a *signaling* NaN. Added in Perl v5.24.\n\nNote the API instability warning in \"setpayload\".\n\nSee \"nan\" for more discussion about \"NaN\".\n\n\"isspace\"\nThis function has been removed as of Perl v5.24. It was very similar to matching against\n\"qr/ ^ [[:space:]]+ $ /x\", which you should convert to use instead. See \"POSIX Character\nClasses\" in perlrecharclass.\n\n\"isupper\"\nThis function has been removed as of Perl v5.24. It was very similar to matching against\n\"qr/ ^ [[:upper:]]+ $ /x\", which you should convert to use instead. See \"POSIX Character\nClasses\" in perlrecharclass.\n\n\"isxdigit\"\nThis function has been removed as of Perl v5.24. It was very similar to matching against\n\"qr/ ^ [[:xdigit:]]+ $ /x\", which you should convert to use instead. See \"POSIX\nCharacter Classes\" in perlrecharclass.\n\n\"j0\"\n\"j1\"\n\"jn\"\n\"y0\"\n\"y1\"\n\"yn\"    The Bessel function of the first kind of the order zero.\n\n\"kill\"  This is identical to Perl's builtin kill() function for sending signals to processes\n(often to terminate them), see \"kill\" in perlfunc.\n\n\"labs\"  Not implemented. (For returning absolute values of long integers.) labs() is C-specific,\nsee \"abs\" in perlfunc instead.\n\n\"lchown\"\nThis is identical to the C function, except the order of arguments is consistent with\nPerl's builtin chown() with the added restriction of only one path, not a list of paths.\nDoes the same thing as the chown() function but changes the owner of a symbolic link\ninstead of the file the symbolic link points to.\n\nPOSIX::lchown($uid, $gid, $filepath);\n\n\"ldexp\" This is identical to the C function ldexp() for multiplying floating point numbers with\npowers of two.\n\n$xquadrupled = POSIX::ldexp($x, 2);\n\n\"ldiv\"  Not implemented. (For computing dividends of long integers.) ldiv() is C-specific, use\n\"/\" and int() instead.\n\n\"lgamma\"\nThe logarithm of the Gamma function [C99]. Added in Perl v5.22.\n\nSee also \"tgamma\".\n\n\"log1p\" Equivalent to \"log(1 + x)\", but more stable results for small argument values [C99].\nAdded in Perl v5.22.\n\n\"log2\"  Logarithm base two [C99]. Added in Perl v5.22.\n\nSee also \"expm1\".\n\n\"logb\"  Integer binary logarithm [C99]. Added in Perl v5.22.\n\nFor example logb(20) is 4, as a floating point number.\n\nSee also \"ilogb\".\n\n\"link\"  This is identical to Perl's builtin link() function for creating hard links into files,\nsee \"link\" in perlfunc.\n\n\"localeconv\"\nGet numeric formatting information. Returns a reference to a hash containing the\nformatting values of the locale that currently underlies the program, regardless of\nwhether or not it is called from within the scope of a \"use locale\". Users of this\nfunction should also read perllocale, which provides a comprehensive discussion of Perl\nlocale handling, including a section devoted to this function. Prior to Perl 5.28, or\nwhen operating in a non thread-safe environment, it should not be used in a threaded\napplication unless it's certain that the underlying locale is C or POSIX. This is\nbecause it otherwise changes the locale, which globally affects all threads\nsimultaneously. Windows platforms starting with Visual Studio 2005 are mostly\nthread-safe, but use of this function in those prior to Visual Studio 2015 can have a\nrace with a thread that has called \"switchtogloballocale\" in perlapi.\n\nHere is how to query the database for the de (Deutsch or German) locale.\n\nmy $loc = POSIX::setlocale( &POSIX::LCALL, \"de\" );\nprint \"Locale: \\\"$loc\\\"\\n\";\nmy $lconv = POSIX::localeconv();\nforeach my $property (qw(\ndecimalpoint\nthousandssep\ngrouping\nintcurrsymbol\ncurrencysymbol\nmondecimalpoint\nmonthousandssep\nmongrouping\npositivesign\nnegativesign\nintfracdigits\nfracdigits\npcsprecedes\npsepbyspace\nncsprecedes\nnsepbyspace\npsignposn\nnsignposn\nintpcsprecedes\nintpsepbyspace\nintncsprecedes\nintnsepbyspace\nintpsignposn\nintnsignposn\n))\n{\nprintf qq(%s: \"%s\",\\n),\n$property, $lconv->{$property};\n}\n\nThe members whose names begin with \"intp\" and \"intn\" were added by POSIX.1-2008 and\nare only available on systems that support them.\n\nA value of -1 returned for numeric entries indicates that the field is not applicable to\nthe locale. This is rare except in the C and related locales, which don't have most\nmonetary values defined. It can also happen, quirkily, in fields that are otherwise\nboolean to indicate that the value is kind of neither true nor false. This happens in\n\"pcsprecedes\" and \"intpcsprecedes\" when the currency symbol neither precedes nor\nsucceeds a positive value but is infixed, by replacing the radix character.\n\nPrior to Perl v5.37.7, empty string fields and numeric fields with value -1 were\nomittted from the returned hash.\n\n\"localtime\"\nThis is identical to Perl's builtin localtime() function for converting seconds since\nthe epoch to a date see \"localtime\" in perlfunc except that POSIX::localtime() must be\nprovided an explicit value (rather than relying on an implicit $):\n\n@localtime = POSIX::localtime(time);    # good\n\n@localtime = localtime();               # good\n\n@localtime = POSIX::localtime();        # throws exception\n\n\"log\"   This is identical to Perl's builtin log() function, returning the natural (*e*-based)\nlogarithm of the numerical argument, see \"log\" in perlfunc.\n\n\"log10\" This is identical to the C function log10(), returning the 10-base logarithm of the\nnumerical argument. You can also use\n\nsub log10 { log($[0]) / log(10) }\n\nor\n\nsub log10 { log($[0]) / 2.30258509299405 }\n\nor\n\nsub log10 { log($[0]) * 0.434294481903252 }\n\n\"longjmp\"\nNot implemented. longjmp() is C-specific: use \"die\" in perlfunc instead.\n\n\"lseek\" Move the file's read/write position. This uses file descriptors such as those obtained\nby calling \"POSIX::open\".\n\n$fd = POSIX::open( \"foo\", &POSIX::ORDONLY );\n$offt = POSIX::lseek( $fd, 0, &POSIX::SEEKSET );\n\nReturns \"undef\" on failure.\n\n\"lrint\" Depending on the current floating point rounding mode, rounds the argument either toward\nnearest (like \"round\"), toward zero (like \"trunc\"), downward (toward negative infinity),\nor upward (toward positive infinity) [C99]. Added in Perl v5.22.\n\nFor the rounding mode, see \"fegetround\".\n\n\"lround\"\nLike \"round\", but as integer, as opposed to floating point [C99]. Added in Perl v5.22.\n\nSee also \"ceil\", \"floor\", \"trunc\".\n\nOwing to an oversight, this is not currently exported by default, or as part of the\n\":mathhc99\" export tag; importing it must therefore be done by explicit name.\n\n\"malloc\"\nNot implemented. malloc() is C-specific. Perl does memory management transparently.\n\n\"mblen\" This is the same as the C function mblen() on unthreaded perls. On threaded perls, it\ntransparently (almost) substitutes the more thread-safe \"mbrlen\"(3), if available,\ninstead of \"mblen\".\n\nCore Perl does not have any support for wide and multibyte locales, except Unicode UTF-8\nlocales. This function, in conjunction with \"mbtowc\" and \"wctomb\" may be used to roll\nyour own decoding/encoding of other types of multi-byte locales.\n\nUse \"undef\" as the first parameter to this function to get the effect of passing NULL as\nthe first parameter to \"mblen\". This resets any shift state to its initial value. The\nreturn value is undefined if \"mbrlen\" was substituted, so you should never rely on it.\n\nWhen the first parameter is a scalar containing a value that either is a PV string or\ncan be forced into one, the return value is the number of bytes occupied by the first\ncharacter of that string; or 0 if that first character is the wide NUL character; or\nnegative if there is an error. This is based on the locale that currently underlies the\nprogram, regardless of whether or not the function is called from Perl code that is\nwithin the scope of \"use locale\". Perl makes no attempt at hiding from your code any\ndifferences in the \"errno\" setting between \"mblen\" and \"mbrlen\". It does set \"errno\" to\n0 before calling them.\n\nThe optional second parameter is ignored if it is larger than the actual length of the\nfirst parameter string.\n\n\"mbtowc\"\nThis is the same as the C function mbtowc() on unthreaded perls. On threaded perls, it\ntransparently (almost) substitutes the more thread-safe \"mbrtowc\"(3), if available,\ninstead of \"mbtowc\".\n\nCore Perl does not have any support for wide and multibyte locales, except Unicode UTF-8\nlocales. This function, in conjunction with \"mblen\" and \"wctomb\" may be used to roll\nyour own decoding/encoding of other types of multi-byte locales.\n\nThe first parameter is a scalar into which, upon success, the wide character represented\nby the multi-byte string contained in the second parameter is stored. The optional third\nparameter is ignored if it is larger than the actual length of the second parameter\nstring.\n\nUse \"undef\" as the second parameter to this function to get the effect of passing NULL\nas the second parameter to \"mbtowc\". This ignores the first parameter, and resets any\nshift state to its initial value. The return value is undefined if \"mbrtowc\" was\nsubstituted, so you should never rely on it.\n\nWhen the second parameter is a scalar containing a value that either is a PV string or\ncan be forced into one, the return value is the number of bytes occupied by the first\ncharacter of that string; or 0 if that first character is the wide NUL character; or\nnegative if there is an error. This is based on the locale that currently underlies the\nprogram, regardless of whether or not the function is called from Perl code that is\nwithin the scope of \"use locale\". Perl makes no attempt at hiding from your code any\ndifferences in the \"errno\" setting between \"mbtowc\" and \"mbrtowc\". It does set \"errno\"\nto 0 before calling them.\n\n\"memchr\"\nNot implemented. memchr() is C-specific, see \"index\" in perlfunc instead.\n\n\"memcmp\"\nNot implemented. memcmp() is C-specific, use \"eq\" instead, see perlop.\n\n\"memcpy\"\nNot implemented. memcpy() is C-specific, use \"=\", see perlop, or see \"substr\" in\nperlfunc.\n\n\"memmove\"\nNot implemented. memmove() is C-specific, use \"=\", see perlop, or see \"substr\" in\nperlfunc.\n\n\"memset\"\nNot implemented. memset() is C-specific, use \"x\" instead, see perlop.\n\n\"mkdir\" This is identical to Perl's builtin mkdir() function for creating directories, see\n\"mkdir\" in perlfunc.\n\n\"mkfifo\"\nThis is similar to the C function mkfifo() for creating FIFO special files.\n\nif (mkfifo($path, $mode)) { ....\n\nReturns \"undef\" on failure. The $mode is similar to the mode of mkdir(), see \"mkdir\" in\nperlfunc, though for \"mkfifo\" you must specify the $mode.\n\n\"mktime\"\nConvert date/time info to a calendar time.\n\nSynopsis:\n\nmktime(sec, min, hour, mday, mon, year, wday = 0,\nyday = 0, isdst = -1)\n\nThe month (\"mon\"), weekday (\"wday\"), and yearday (\"yday\") begin at zero, *i.e.*, January\nis 0, not 1; Sunday is 0, not 1; January 1st is 0, not 1. The year (\"year\") is given in\nyears since 1900; *i.e.*, the year 1995 is 95; the year 2001 is 101. Consult your\nsystem's mktime() manpage for details about these and the other arguments.\n\nCalendar time for December 12, 1995, at 10:30 am.\n\n$timet = POSIX::mktime( 0, 30, 10, 12, 11, 95 );\nprint \"Date = \", POSIX::ctime($timet);\n\nReturns \"undef\" on failure.\n\n\"modf\"  Return the integral and fractional parts of a floating-point number.\n\n($fractional, $integral) = POSIX::modf( 3.14 );\n\nSee also \"round\".\n\n\"NaN\"   The not-a-number as a constant:\n\nuse POSIX qw(NaN);\nmy $nan = NaN;\n\nSee also \"nan\", \"/isnan\", and \"fpclassify\".\n\n\"nan\"\nmy $nan = nan();\n\nReturns \"NaN\", not-a-number [C99]. Added in Perl v5.22.\n\nThe returned NaN is always a *quiet* NaN, as opposed to *signaling*.\n\nWith an argument, can be used to generate a NaN with *payload*. The argument is first\ninterpreted as a floating point number, but then any fractional parts are truncated\n(towards zero), and the value is interpreted as an unsigned integer. The bits of this\ninteger are stored in the unused bits of the NaN.\n\nThe result has a dual nature: it is a NaN, but it also carries the integer inside it.\nThe integer can be retrieved with \"getpayload\". Note, though, that the payload is not\npropagated, not even on copies, and definitely not in arithmetic operations.\n\nHow many bits fit in the NaN depends on what kind of floating points are being used, but\non the most common platforms (64-bit IEEE 754, or the x86 80-bit long doubles) there are\n51 and 61 bits available, respectively. (There would be 52 and 62, but the\nquiet/signaling bit of NaNs takes away one.) However, because of the floating-point-to-\ninteger-and-back conversions, please test carefully whether you get back what you put\nin. If your integers are only 32 bits wide, you probably should not rely on more than 32\nbits of payload.\n\nWhether a \"signaling\" NaN is in any way different from a \"quiet\" NaN, depends on the\nplatform. Also note that the payload of the default NaN (no argument to nan()) is not\nnecessarily zero, use \"setpayload\" to explicitly set the payload. On some platforms like\nthe 32-bit x86, (unless using the 80-bit long doubles) the signaling bit is not\nsupported at all.\n\nSee also \"isnan\", \"NaN\", \"setpayload\" and \"issignaling\".\n\n\"nearbyint\"\nReturns the nearest integer to the argument, according to the current rounding mode (see\n\"fegetround\") [C99]. Added in Perl v5.22.\n\n\"nextafter\"\nReturns the next representable floating point number after \"x\" in the direction of \"y\"\n[C99]. Added in Perl v5.22.\n\nmy $nextafter = POSIX::nextafter($x, $y);\n\nLike \"nexttoward\", but potentially less accurate.\n\n\"nexttoward\"\nReturns the next representable floating point number after \"x\" in the direction of \"y\"\n[C99]. Added in Perl v5.22.\n\nmy $nexttoward = POSIX::nexttoward($x, $y);\n\nLike \"nextafter\", but potentially more accurate.\n\n\"nice\"  This is similar to the C function nice(), for changing the scheduling preference of the\ncurrent process. Positive arguments mean a more polite process, negative values a more\nneedy process. Normal (non-root) user processes can only change towards being more\npolite.\n\nReturns \"undef\" on failure.\n\n\"offsetof\"\nNot implemented. offsetof() is C-specific, you probably want to see \"pack\" in perlfunc\ninstead.\n\n\"open\"  Open a file for reading for writing. This returns file descriptors, not Perl\nfilehandles. Use \"POSIX::close\" to close the file.\n\nOpen a file read-only with mode 0666.\n\n$fd = POSIX::open( \"foo\" );\n\nOpen a file for read and write.\n\n$fd = POSIX::open( \"foo\", &POSIX::ORDWR );\n\nOpen a file for write, with truncation.\n\n$fd = POSIX::open(\n\"foo\", &POSIX::OWRONLY | &POSIX::OTRUNC\n);\n\nCreate a new file with mode 0640. Set up the file for writing.\n\n$fd = POSIX::open(\n\"foo\", &POSIX::OCREAT | &POSIX::OWRONLY, 0640\n);\n\nReturns \"undef\" on failure.\n\nSee also \"sysopen\" in perlfunc.\n\n\"opendir\"\nOpen a directory for reading.\n\n$dir = POSIX::opendir( \"/var\" );\n@files = POSIX::readdir( $dir );\nPOSIX::closedir( $dir );\n\nReturns \"undef\" on failure.\n\n\"pathconf\"\nRetrieves the value of a configurable limit on a file or directory.\n\nThe following will determine the maximum length of the longest allowable pathname on the\nfilesystem which holds \"/var\".\n\n$pathmax = POSIX::pathconf( \"/var\",\n&POSIX::PCPATHMAX );\n\nReturns \"undef\" on failure.\n\n\"pause\" This is similar to the C function pause(), which suspends the execution of the current\nprocess until a signal is received.\n\nReturns \"undef\" on failure.\n\n\"perror\"\nThis is identical to the C function perror(), which outputs to the standard error stream\nthe specified message followed by \": \" and the current error string. Use the warn()\nfunction and the $! variable instead, see \"warn\" in perlfunc and \"$ERRNO\" in perlvar.\n\n\"pipe\"  Create an interprocess channel. This returns file descriptors like those returned by\n\"POSIX::open\".\n\nmy ($read, $write) = POSIX::pipe();\nPOSIX::write( $write, \"hello\", 5 );\nPOSIX::read( $read, $buf, 5 );\n\nSee also \"pipe\" in perlfunc.\n\n\"pow\"   Computes $x raised to the power $exponent.\n\n$ret = POSIX::pow( $x, $exponent );\n\nYou can also use the \"\" operator, see perlop.\n\n\"printf\"\nFormats and prints the specified arguments to \"STDOUT\". See also \"printf\" in perlfunc.\n\n\"putc\"  Not implemented. putc() is C-specific, see \"print\" in perlfunc instead.\n\n\"putchar\"\nNot implemented. putchar() is C-specific, see \"print\" in perlfunc instead.\n\n\"puts\"  Not implemented. puts() is C-specific, see \"print\" in perlfunc instead.\n\n\"qsort\" Not implemented. qsort() is C-specific, see \"sort\" in perlfunc instead.\n\n\"raise\" Sends the specified signal to the current process. See also \"kill\" in perlfunc and the\n$$ in \"$PID\" in perlvar.\n\n\"rand\"  Not implemented. rand() is non-portable, see \"rand\" in perlfunc instead.\n\n\"read\"  Read from a file. This uses file descriptors such as those obtained by calling\n\"POSIX::open\". If the buffer $buf is not large enough for the read then Perl will extend\nit to make room for the request.\n\n$fd = POSIX::open( \"foo\", &POSIX::ORDONLY );\n$bytes = POSIX::read( $fd, $buf, 3 );\n\nReturns \"undef\" on failure.\n\nSee also \"sysread\" in perlfunc.\n\n\"readdir\"\nThis is identical to Perl's builtin readdir() function for reading directory entries,\nsee \"readdir\" in perlfunc.\n\n\"realloc\"\nNot implemented. realloc() is C-specific. Perl does memory management transparently.\n\n\"remainder\"\nGiven \"x\" and \"y\", returns the value \"x - n*y\", where \"n\" is the integer closest to\n\"x\"/\"y\" [C99]. Added in Perl v5.22.\n\nmy $remainder = POSIX::remainder($x, $y)\n\nSee also \"remquo\".\n\n\"remove\"\nDeletes a name from the filesystem. Calls \"unlink\" in perlfunc for files and \"rmdir\" in\nperlfunc for directories.\n\n\"remquo\"\nLike \"remainder\" but also returns the low-order bits of the quotient (n) [C99]. Added in\nPerl v5.22.\n\n(This is quite esoteric interface, mainly used to implement numerical algorithms.)\n\n\"rename\"\nThis is identical to Perl's builtin rename() function for renaming files, see \"rename\"\nin perlfunc.\n\n\"rewind\"\nSeeks to the beginning of the file.\n\n\"rewinddir\"\nThis is identical to Perl's builtin rewinddir() function for rewinding directory entry\nstreams, see \"rewinddir\" in perlfunc.\n\n\"rint\"  Identical to \"lrint\".\n\n\"rmdir\" This is identical to Perl's builtin rmdir() function for removing (empty) directories,\nsee \"rmdir\" in perlfunc.\n\n\"round\" Returns the integer (but still as floating point) nearest to the argument [C99]. Added\nin Perl v5.22.\n\nSee also \"ceil\", \"floor\", \"lround\", \"modf\", and \"trunc\".\n\n\"scalbn\"\nReturns \"x * 2y\" [C99]. Added in Perl v5.22.\n\nSee also \"frexp\" and \"ldexp\".\n\n\"scanf\" Not implemented. scanf() is C-specific, use <> and regular expressions instead, see\nperlre.\n\n\"setgid\"\nSets the real group identifier and the effective group identifier for this process.\nSimilar to assigning a value to the Perl's builtin $) variable, see \"$EGID\" in perlvar,\nexcept that the latter will change only the real user identifier, and that the setgid()\nuses only a single numeric argument, as opposed to a space-separated list of numbers.\n\n\"setjmp\"\nNot implemented. setjmp() is C-specific: use \"eval {}\" instead, see \"eval\" in perlfunc.\n\n\"setlocale\"\nWARNING! Prior to Perl 5.28 or on a system that does not support thread-safe locale\noperations, do NOT use this function in a thread. The locale will change in all other\nthreads at the same time, and should your thread get paused by the operating system, and\nanother started, that thread will not have the locale it is expecting. On some\nplatforms, there can be a race leading to segfaults if two threads call this function\nnearly simultaneously. This warning does not apply on unthreaded builds, or on perls\nwhere \"${^SAFELOCALES}\" exists and is non-zero; namely Perl 5.28 and later compiled to\nbe locale-thread-safe.\n\nThis function modifies and queries the program's underlying locale. Users of this\nfunction should read perllocale, whch provides a comprehensive discussion of Perl locale\nhandling, knowledge of which is necessary to properly use this function. It contains a\nsection devoted to this function. The discussion here is merely a summary reference for\nsetlocale(). Note that Perl itself is almost entirely unaffected by the locale except\nwithin the scope of \"use locale\". (Exceptions are listed in \"Not within the scope of\n\"use locale\"\" in perllocale, and locale-dependent functions within the POSIX module ARE\nalways affected by the current locale.)\n\nThe following examples assume\n\nuse POSIX qw(setlocale LCALL LCCTYPE);\n\nhas been issued.\n\nThe following will set the traditional UNIX system locale behavior (the second argument\n\"C\").\n\n$loc = setlocale( LCALL, \"C\" );\n\nThe following will query the current \"LCCTYPE\" category. (No second argument means\n'query'.)\n\n$loc = setlocale( LCCTYPE );\n\nThe following will set the \"LCCTYPE\" behaviour according to the locale environment\nvariables (the second argument \"\"). Please see your system's setlocale(3) documentation\nfor the locale environment variables' meaning or consult perllocale.\n\n$loc = setlocale( LCCTYPE, \"\" );\n\nThe following will set the \"LCCOLLATE\" behaviour to Argentinian Spanish. NOTE: The\nnaming and availability of locales depends on your operating system. Please consult\nperllocale for how to find out which locales are available in your system.\n\n$loc = setlocale( LCCOLLATE, \"esAR.ISO8859-1\" );\n\n\"setpayload\"\nuse POSIX ':nanpayload';\nsetpayload($var, $payload);\n\nSets the \"NaN\" payload of var. Added in Perl v5.24.\n\nNOTE: the NaN payload APIs are based on the latest (as of June 2015) proposed ISO C\ninterfaces, but they are not yet a standard. Things may change.\n\nSee \"nan\" for more discussion about \"NaN\".\n\nSee also \"setpayloadsig\", \"isnan\", \"getpayload\", and \"issignaling\".\n\n\"setpayloadsig\"\nuse POSIX ':nanpayload';\nsetpayloadsig($var, $payload);\n\nLike \"setpayload\" but also makes the NaN *signaling*. Added in Perl v5.24.\n\nDepending on the platform the NaN may or may not behave differently.\n\nNote the API instability warning in \"setpayload\".\n\nNote that because how the floating point formats work out, on the most common platforms\nsignaling payload of zero is best avoided, since it might end up being identical to\n\"+Inf\".\n\nSee also \"nan\", \"isnan\", \"getpayload\", and \"issignaling\".\n\n\"setpgid\"\nThis is similar to the C function setpgid() for setting the process group identifier of\nthe current process.\n\nReturns \"undef\" on failure.\n\n\"setsid\"\nThis is identical to the C function setsid() for setting the session identifier of the\ncurrent process.\n\n\"setuid\"\nSets the real user identifier and the effective user identifier for this process.\nSimilar to assigning a value to the Perl's builtin $< variable, see \"$UID\" in perlvar,\nexcept that the latter will change only the real user identifier.\n\n\"sigaction\"\nDetailed signal management. This uses \"POSIX::SigAction\" objects for the \"action\" and\n\"oldaction\" arguments (the oldaction can also be just a hash reference). Consult your\nsystem's \"sigaction\" manpage for details, see also \"POSIX::SigRt\".\n\nSynopsis:\n\nsigaction(signal, action, oldaction = 0)\n\nReturns \"undef\" on failure. The \"signal\" must be a number (like \"SIGHUP\"), not a string\n(like \"SIGHUP\"), though Perl does try hard to understand you.\n\nIf you use the \"SASIGINFO\" flag, the signal handler will in addition to the first\nargument, the signal name, also receive a second argument, a hash reference, inside\nwhich are the following keys with the following semantics, as defined by POSIX/SUSv3:\n\nsigno       the signal number\nerrno       the error number\ncode        if this is zero or less, the signal was sent by\na user process and the uid and pid make sense,\notherwise the signal was sent by the kernel\n\nThe constants for specific \"code\" values can be imported individually or using the\n\":signalhsicode\" tag, since Perl v5.24.\n\nThe following are also defined by POSIX/SUSv3, but unfortunately not very widely\nimplemented:\n\npid         the process id generating the signal\nuid         the uid of the process id generating the signal\nstatus      exit value or signal for SIGCHLD\nband        band event for SIGPOLL\naddr        address of faulting instruction or memory\nreference for SIGILL, SIGFPE, SIGSEGV or SIGBUS\n\nA third argument is also passed to the handler, which contains a copy of the raw binary\ncontents of the \"siginfo\" structure: if a system has some non-POSIX fields, this third\nargument is where to unpack() them from.\n\nNote that not all \"siginfo\" values make sense simultaneously (some are valid only for\ncertain signals, for example), and not all values make sense from Perl perspective, you\nshould to consult your system's \"sigaction\" and possibly also \"siginfo\" documentation.\n\n\"siglongjmp\"\nNot implemented. siglongjmp() is C-specific: use \"die\" in perlfunc instead.\n\n\"signbit\"\nReturns zero for positive arguments, non-zero for negative arguments [C99]. Added in\nPerl v5.22.\n\n\"sigpending\"\nExamine signals that are blocked and pending. This uses \"POSIX::SigSet\" objects for the\n\"sigset\" argument. Consult your system's \"sigpending\" manpage for details.\n\nSynopsis:\n\nsigpending(sigset)\n\nReturns \"undef\" on failure.\n\n\"sigprocmask\"\nChange and/or examine calling process's signal mask. This uses \"POSIX::SigSet\" objects\nfor the \"sigset\" and \"oldsigset\" arguments. Consult your system's \"sigprocmask\" manpage\nfor details.\n\nSynopsis:\n\nsigprocmask(how, sigset, oldsigset = 0)\n\nReturns \"undef\" on failure.\n\nNote that you can't reliably block or unblock a signal from its own signal handler if\nyou're using safe signals. Other signals can be blocked or unblocked reliably.\n\n\"sigsetjmp\"\nNot implemented. sigsetjmp() is C-specific: use \"eval {}\" instead, see \"eval\" in\nperlfunc.\n\n\"sigsuspend\"\nInstall a signal mask and suspend process until signal arrives. This uses\n\"POSIX::SigSet\" objects for the \"signalmask\" argument. Consult your system's\n\"sigsuspend\" manpage for details.\n\nSynopsis:\n\nsigsuspend(signalmask)\n\nReturns \"undef\" on failure.\n\n\"sin\"   This is identical to Perl's builtin sin() function for returning the sine of the\nnumerical argument, see \"sin\" in perlfunc. See also Math::Trig.\n\n\"sinh\"  This is identical to the C function sinh() for returning the hyperbolic sine of the\nnumerical argument. See also Math::Trig.\n\n\"sleep\" This is functionally identical to Perl's builtin sleep() function for suspending the\nexecution of the current for process for certain number of seconds, see \"sleep\" in\nperlfunc. There is one significant difference, however: POSIX::sleep() returns the\nnumber of unslept seconds, while the CORE::sleep() returns the number of slept seconds.\n\n\"sprintf\"\nThis is similar to Perl's builtin sprintf() function for returning a string that has the\narguments formatted as requested, see \"sprintf\" in perlfunc.\n\n\"sqrt\"  This is identical to Perl's builtin sqrt() function. for returning the square root of\nthe numerical argument, see \"sqrt\" in perlfunc.\n\n\"srand\" Give a seed the pseudorandom number generator, see \"srand\" in perlfunc.\n\n\"sscanf\"\nNot implemented. sscanf() is C-specific, use regular expressions instead, see perlre.\n\n\"stat\"  This is identical to Perl's builtin stat() function for returning information about\nfiles and directories.\n\n\"strcat\"\nNot implemented. strcat() is C-specific, use \".=\" instead, see perlop.\n\n\"strchr\"\nNot implemented. strchr() is C-specific, see \"index\" in perlfunc instead.\n\n\"strcmp\"\nNot implemented. strcmp() is C-specific, use \"eq\" or \"cmp\" instead, see perlop.\n\n\"strcoll\"\nThis is identical to the C function strcoll() for collating (comparing) strings\ntransformed using the strxfrm() function. Not really needed since Perl can do this\ntransparently, see perllocale.\n\nBeware that in a UTF-8 locale, anything you pass to this function must be in UTF-8; and\nwhen not in a UTF-8 locale, anything passed must not be UTF-8 encoded.\n\nNote also that it doesn't make sense for a string to be encoded in one locale (say,\nISO-8859-6, Arabic) and to collate it based on another (like ISO-8859-7, Greek). The\nresults will be essentially meaningless.\n\n\"strcpy\"\nNot implemented. strcpy() is C-specific, use \"=\" instead, see perlop.\n\n\"strcspn\"\nNot implemented. strcspn() is C-specific, use regular expressions instead, see perlre.\n\n\"strerror\"\nReturns the error string for the specified errno. Identical to the string form of $!,\nsee \"$ERRNO\" in perlvar.\n\n\"strftime\"\nConvert date and time information to string. Returns the string.\n\nSynopsis:\n\nstrftime(fmt, sec, min, hour, mday, mon, year,\nwday = -1, yday = -1, isdst = -1)\n\nThe month (\"mon\"), weekday (\"wday\"), and yearday (\"yday\") begin at zero, *i.e.*, January\nis 0, not 1; Sunday is 0, not 1; January 1st is 0, not 1. The year (\"year\") is given in\nyears since 1900, *i.e.*, the year 1995 is 95; the year 2001 is 101. Consult your\nsystem's strftime() manpage for details about these and the other arguments.\n\nIf you want your code to be portable, your format (\"fmt\") argument should use only the\nconversion specifiers defined by the ANSI C standard (C99, to play safe). These are\n\"aAbBcdHIjmMpSUwWxXyYZ%\". But even then, the results of some of the conversion\nspecifiers are non-portable. For example, the specifiers \"aAbBcpZ\" change according to\nthe locale settings of the user, and both how to set locales (the locale names) and what\noutput to expect are non-standard. The specifier \"c\" changes according to the timezone\nsettings of the user and the timezone computation rules of the operating system. The \"Z\"\nspecifier is notoriously unportable since the names of timezones are non-standard.\nSticking to the numeric specifiers is the safest route.\n\nThe given arguments are made consistent as though by calling mktime() before calling\nyour system's strftime() function, except that the \"isdst\" value is not affected.\n\nThe string for Tuesday, December 12, 1995.\n\n$str = POSIX::strftime( \"%A, %B %d, %Y\",\n0, 0, 0, 12, 11, 95, 2 );\nprint \"$str\\n\";\n\n\"strlen\"\nNot implemented. strlen() is C-specific, use length() instead, see \"length\" in perlfunc.\n\n\"strncat\"\nNot implemented. strncat() is C-specific, use \".=\" instead, see perlop.\n\n\"strncmp\"\nNot implemented. strncmp() is C-specific, use \"eq\" instead, see perlop.\n\n\"strncpy\"\nNot implemented. strncpy() is C-specific, use \"=\" instead, see perlop.\n\n\"strpbrk\"\nNot implemented. strpbrk() is C-specific, use regular expressions instead, see perlre.\n\n\"strrchr\"\nNot implemented. strrchr() is C-specific, see \"rindex\" in perlfunc instead.\n\n\"strspn\"\nNot implemented. strspn() is C-specific, use regular expressions instead, see perlre.\n\n\"strstr\"\nThis is identical to Perl's builtin index() function, see \"index\" in perlfunc.\n\n\"strtod\"\nString to double translation. Returns the parsed number and the number of characters in\nthe unparsed portion of the string. Truly POSIX-compliant systems set $! ($ERRNO) to\nindicate a translation error, so clear $! before calling \"strtod\". However, non-POSIX\nsystems may not check for overflow, and therefore will never set $!.\n\n\"strtod\" respects any POSIX setlocale() \"LCNUMERIC\" settings, regardless of whether or\nnot it is called from Perl code that is within the scope of \"use locale\". Prior to Perl\n5.28, or when operating in a non thread-safe environment, it should not be used in a\nthreaded application unless it's certain that the underlying locale is C or POSIX. This\nis because it otherwise changes the locale, which globally affects all threads\nsimultaneously.\n\nTo parse a string $str as a floating point number use\n\n$! = 0;\n($num, $nunparsed) = POSIX::strtod($str);\n\nThe second returned item and $! can be used to check for valid input:\n\nif (($str eq '') || ($nunparsed != 0) || $!) {\ndie \"Non-numeric input $str\" . ($! ? \": $!\\n\" : \"\\n\");\n}\n\nWhen called in a scalar context \"strtod\" returns the parsed number.\n\n\"strtok\"\nNot implemented. strtok() is C-specific, use regular expressions instead, see perlre, or\n\"split\" in perlfunc.\n\n\"strtol\"\nString to (long) integer translation. Returns the parsed number and the number of\ncharacters in the unparsed portion of the string. Truly POSIX-compliant systems set $!\n($ERRNO) to indicate a translation error, so clear $! before calling \"strtol\". However,\nnon-POSIX systems may not check for overflow, and therefore will never set $!.\n\n\"strtol\" should respect any POSIX *setlocale()* settings.\n\nTo parse a string $str as a number in some base $base use\n\n$! = 0;\n($num, $nunparsed) = POSIX::strtol($str, $base);\n\nThe base should be zero or between 2 and 36, inclusive. When the base is zero or omitted\n\"strtol\" will use the string itself to determine the base: a leading \"0x\" or \"0X\" means\nhexadecimal; a leading \"0\" means octal; any other leading characters mean decimal. Thus,\n\"1234\" is parsed as a decimal number, \"01234\" as an octal number, and \"0x1234\" as a\nhexadecimal number.\n\nThe second returned item and $! can be used to check for valid input:\n\nif (($str eq '') || ($nunparsed != 0) || !$!) {\ndie \"Non-numeric input $str\" . $! ? \": $!\\n\" : \"\\n\";\n}\n\nWhen called in a scalar context \"strtol\" returns the parsed number.\n\n\"strtold\"\nLike \"strtod\" but for long doubles. Defined only if the system supports long doubles.\n\n\"strtoul\"\nString to unsigned (long) integer translation. strtoul() is identical to strtol() except\nthat strtoul() only parses unsigned integers. See \"strtol\" for details.\n\nNote: Some vendors supply strtod() and strtol() but not strtoul(). Other vendors that do\nsupply strtoul() parse \"-1\" as a valid value.\n\n\"strxfrm\"\nString transformation. Returns the transformed string.\n\n$dst = POSIX::strxfrm( $src );\n\nUsed with \"eq\" or \"cmp\" as an alternative to \"strcoll\".\n\nNot really needed since Perl can do this transparently, see perllocale.\n\nUnlike the libc \"strxfrm\", this allows NUL characters in the input $src.\n\nIt doesn't make sense for a string to be encoded in one locale (say, ISO-8859-6, Arabic)\nand to collate it based on another (like ISO-8859-7, Greek). Perl assumes that the\ncurrent \"LCCTYPE\" locale correctly represents the encoding of $src, and ignores the\nvalue of \"LCCOLLATE\".\n\n\"sysconf\"\nRetrieves values of system configurable variables.\n\nThe following will get the machine's clock speed.\n\n$clockticks = POSIX::sysconf( &POSIX::SCCLKTCK );\n\nReturns \"undef\" on failure.\n\n\"system\"\nThis is identical to Perl's builtin system() function, see \"system\" in perlfunc.\n\n\"tan\"   This is identical to the C function tan(), returning the tangent of the numerical\nargument. See also Math::Trig.\n\n\"tanh\"  This is identical to the C function tanh(), returning the hyperbolic tangent of the\nnumerical argument. See also Math::Trig.\n\n\"tcdrain\"\nThis is similar to the C function tcdrain() for draining the output queue of its\nargument stream.\n\nReturns \"undef\" on failure.\n\n\"tcflow\"\nThis is similar to the C function tcflow() for controlling the flow of its argument\nstream.\n\nReturns \"undef\" on failure.\n\n\"tcflush\"\nThis is similar to the C function tcflush() for flushing the I/O buffers of its argument\nstream.\n\nReturns \"undef\" on failure.\n\n\"tcgetpgrp\"\nThis is identical to the C function tcgetpgrp() for returning the process group\nidentifier of the foreground process group of the controlling terminal.\n\n\"tcsendbreak\"\nThis is similar to the C function tcsendbreak() for sending a break on its argument\nstream.\n\nReturns \"undef\" on failure.\n\n\"tcsetpgrp\"\nThis is similar to the C function tcsetpgrp() for setting the process group identifier\nof the foreground process group of the controlling terminal.\n\nReturns \"undef\" on failure.\n\n\"tgamma\"\nThe Gamma function [C99]. Added in Perl v5.22.\n\nSee also \"lgamma\".\n\n\"time\"  This is identical to Perl's builtin time() function for returning the number of seconds\nsince the epoch (whatever it is for the system), see \"time\" in perlfunc.\n\n\"times\" The times() function returns elapsed realtime since some point in the past (such as\nsystem startup), user and system times for this process, and user and system times used\nby child processes. All times are returned in clock ticks.\n\n($realtime, $user, $system, $cuser, $csystem)\n= POSIX::times();\n\nNote: Perl's builtin times() function returns four values, measured in seconds.\n\n\"tmpfile\"\nNot implemented. Use method IO::File::newtmpfile() instead, or see File::Temp.\n\n\"tmpnam\"\nFor security reasons, which are probably detailed in your system's documentation for the\nC library tmpnam() function, this interface is no longer available since Perl v5.26;\ninstead use File::Temp.\n\n\"tolower\"\nThis function has been removed as of Perl v5.26. This is identical to the C function,\nexcept that it can apply to a single character or to a whole string, and currently\noperates as if the locale always is \"C\". Consider using the lc() function, see \"lc\" in\nperlfunc, see \"lc\" in perlfunc, or the equivalent \"\\L\" operator inside doublequotish\nstrings.\n\n\"toupper\"\nThis function has been removed as of Perl v5.26. This is similar to the C function,\nexcept that it can apply to a single character or to a whole string, and currently\noperates as if the locale always is \"C\". Consider using the uc() function, see \"uc\" in\nperlfunc, or the equivalent \"\\U\" operator inside doublequotish strings.\n\n\"trunc\" Returns the integer toward zero from the argument [C99]. Added in Perl v5.22.\n\nSee also \"ceil\", \"floor\", and \"round\".\n\n\"ttyname\"\nThis is identical to the C function ttyname() for returning the name of the current\nterminal.\n\n\"tzname\"\nRetrieves the time conversion information from the \"tzname\" variable.\n\nPOSIX::tzset();\n($std, $dst) = POSIX::tzname();\n\n\"tzset\" This is identical to the C function tzset() for setting the current timezone based on\nthe environment variable \"TZ\", to be used by ctime(), localtime(), mktime(), and\nstrftime() functions.\n\n\"umask\" This is identical to Perl's builtin umask() function for setting (and querying) the file\ncreation permission mask, see \"umask\" in perlfunc.\n\n\"uname\" Get name of current operating system.\n\n($sysname, $nodename, $release, $version, $machine)\n= POSIX::uname();\n\nNote that the actual meanings of the various fields are not that well standardized, do\nnot expect any great portability. The $sysname might be the name of the operating\nsystem, the $nodename might be the name of the host, the $release might be the (major)\nrelease number of the operating system, the $version might be the (minor) release number\nof the operating system, and the $machine might be a hardware identifier. Maybe.\n\n\"ungetc\"\nNot implemented. Use method IO::Handle::ungetc() instead.\n\n\"unlink\"\nThis is identical to Perl's builtin unlink() function for removing files, see \"unlink\"\nin perlfunc.\n\n\"utime\" This is identical to Perl's builtin utime() function for changing the time stamps of\nfiles and directories, see \"utime\" in perlfunc.\n\n\"vfprintf\"\nNot implemented. vfprintf() is C-specific, see \"printf\" in perlfunc instead.\n\n\"vprintf\"\nNot implemented. vprintf() is C-specific, see \"printf\" in perlfunc instead.\n\n\"vsprintf\"\nNot implemented. vsprintf() is C-specific, see \"sprintf\" in perlfunc instead.\n\n\"wait\"  This is identical to Perl's builtin wait() function, see \"wait\" in perlfunc.\n\n\"waitpid\"\nWait for a child process to change state. This is identical to Perl's builtin waitpid()\nfunction, see \"waitpid\" in perlfunc.\n\n$pid = POSIX::waitpid( -1, POSIX::WNOHANG );\nprint \"status = \", ($? / 256), \"\\n\";\n\nSee \"mblen\".\n\n\"wctomb\"\nThis is the same as the C function wctomb() on unthreaded perls. On threaded perls, it\ntransparently (almost) substitutes the more thread-safe \"wcrtomb\"(3), if available,\ninstead of \"wctomb\".\n\nCore Perl does not have any support for wide and multibyte locales, except Unicode UTF-8\nlocales. This function, in conjunction with \"mblen\" and \"mbtowc\" may be used to roll\nyour own decoding/encoding of other types of multi-byte locales.\n\nUse \"undef\" as the first parameter to this function to get the effect of passing NULL as\nthe first parameter to \"wctomb\". This ignores the second parameter, and resets any shift\nstate to its initial value. The return value is undefined if \"wcrtomb\" was substituted,\nso you should never rely on it.\n\nWhen the first parameter is a scalar, the code point contained in the scalar second\nparameter is converted into a multi-byte string and stored into the first parameter\nscalar. This is based on the locale that currently underlies the program, regardless of\nwhether or not the function is called from Perl code that is within the scope of\n\"use locale\". The return value is the number of bytes stored; or negative if the code\npoint isn't representable in the current locale. Perl makes no attempt at hiding from\nyour code any differences in the \"errno\" setting between \"wctomb\" and \"wcrtomb\". It does\nset \"errno\" to 0 before calling them.\n\n\"write\" Write to a file. This uses file descriptors such as those obtained by calling\n\"POSIX::open\".\n\n$fd = POSIX::open( \"foo\", &POSIX::OWRONLY );\n$buf = \"hello\";\n$bytes = POSIX::write( $fd, $buf, 5 );\n\nReturns \"undef\" on failure.\n\nSee also \"syswrite\" in perlfunc.\n",
            "subsections": []
        },
        "CLASSES": {
            "content": "\"POSIX::SigAction\"\n\"new\"   Creates a new \"POSIX::SigAction\" object which corresponds to the C \"struct sigaction\".\nThis object will be destroyed automatically when it is no longer needed. The first\nparameter is the handler, a sub reference. The second parameter is a \"POSIX::SigSet\"\nobject, it defaults to the empty set. The third parameter contains the \"saflags\", it\ndefaults to 0.\n\n$sigset = POSIX::SigSet->new(SIGINT, SIGQUIT);\n$sigaction = POSIX::SigAction->new(\n\\&handler, $sigset, &POSIX::SANOCLDSTOP\n);\n\nThis \"POSIX::SigAction\" object is intended for use with the POSIX::sigaction() function.\n\n\"handler\"\n\"mask\"\n\"flags\" accessor functions to get/set the values of a SigAction object.\n\n$sigset = $sigaction->mask;\n$sigaction->flags(&POSIX::SARESTART);\n\n\"safe\"  accessor function for the \"safe signals\" flag of a SigAction object; see perlipc for\ngeneral information on safe (a.k.a. \"deferred\") signals. If you wish to handle a signal\nsafely, use this accessor to set the \"safe\" flag in the \"POSIX::SigAction\" object:\n\n$sigaction->safe(1);\n\nYou may also examine the \"safe\" flag on the output action object which is filled in when\ngiven as the third parameter to POSIX::sigaction():\n\nsigaction(SIGINT, $newaction, $oldaction);\nif ($oldaction->safe) {\n# previous SIGINT handler used safe signals\n}\n\n\"POSIX::SigRt\"\n%SIGRT  A hash of the POSIX realtime signal handlers. It is an extension of the standard %SIG,\nthe $POSIX::SIGRT{SIGRTMIN} is roughly equivalent to $SIG{SIGRTMIN}, but the right POSIX\nmoves (see below) are made with the \"POSIX::SigSet\" and \"POSIX::sigaction\" instead of\naccessing the %SIG.\n\nYou can set the %POSIX::SIGRT elements to set the POSIX realtime signal handlers, use\n\"delete\" and \"exists\" on the elements, and use \"scalar\" on the %POSIX::SIGRT to find out\nhow many POSIX realtime signals there are available \"(SIGRTMAX - SIGRTMIN + 1\", the\n\"SIGRTMAX\" is a valid POSIX realtime signal).\n\nSetting the %SIGRT elements is equivalent to calling this:\n\nsub new {\nmy ($rtsig, $handler, $flags) = @;\nmy $sigset = POSIX::SigSet($rtsig);\nmy $sigact = POSIX::SigAction->new($handler,$sigset,$flags);\nsigaction($rtsig, $sigact);\n}\n\nThe flags default to zero, if you want something different you can either use \"local\" on\n$POSIX::SigRt::SIGACTIONFLAGS, or you can derive from POSIX::SigRt and define your own\nnew() (the tied hash STORE method of the %SIGRT calls \"new($rtsig, $handler,\n$SIGACTIONFLAGS)\", where the $rtsig ranges from zero to \"SIGRTMAX - SIGRTMIN + 1)\".\n\nJust as with any signal, you can use \"sigaction($rtsig, undef, $oa)\" to retrieve the\ninstalled signal handler (or, rather, the signal action).\n\nNOTE: whether POSIX realtime signals really work in your system, or whether Perl has\nbeen compiled so that it works with them, is outside of this discussion.\n\n\"SIGRTMIN\"\nReturn the minimum POSIX realtime signal number available, or \"undef\" if no POSIX\nrealtime signals are available.\n\n\"SIGRTMAX\"\nReturn the maximum POSIX realtime signal number available, or \"undef\" if no POSIX\nrealtime signals are available.\n\n\"POSIX::SigSet\"\n\"new\"   Create a new SigSet object. This object will be destroyed automatically when it is no\nlonger needed. Arguments may be supplied to initialize the set.\n\nCreate an empty set.\n\n$sigset = POSIX::SigSet->new;\n\nCreate a set with \"SIGUSR1\".\n\n$sigset = POSIX::SigSet->new( &POSIX::SIGUSR1 );\n\nThrows an error if any of the signals supplied cannot be added to the set.\n\n\"addset\"\nAdd a signal to a SigSet object.\n\n$sigset->addset( &POSIX::SIGUSR2 );\n\nReturns \"undef\" on failure.\n\n\"delset\"\nRemove a signal from the SigSet object.\n\n$sigset->delset( &POSIX::SIGUSR2 );\n\nReturns \"undef\" on failure.\n\n\"emptyset\"\nInitialize the SigSet object to be empty.\n\n$sigset->emptyset();\n\nReturns \"undef\" on failure.\n\n\"fillset\"\nInitialize the SigSet object to include all signals.\n\n$sigset->fillset();\n\nReturns \"undef\" on failure.\n\n\"ismember\"\nTests the SigSet object to see if it contains a specific signal.\n\nif( $sigset->ismember( &POSIX::SIGUSR1 ) ){\nprint \"contains SIGUSR1\\n\";\n}\n\n\"POSIX::Termios\"\n\"new\"   Create a new Termios object. This object will be destroyed automatically when it is no\nlonger needed. A Termios object corresponds to the \"termios\" C struct. new() mallocs a\nnew one, getattr() fills it from a file descriptor, and setattr() sets a file\ndescriptor's parameters to match Termios' contents.\n\n$termios = POSIX::Termios->new;\n\n\"getattr\"\nGet terminal control attributes.\n\nObtain the attributes for \"stdin\".\n\n$termios->getattr( 0 ) # Recommended for clarity.\n$termios->getattr()\n\nObtain the attributes for stdout.\n\n$termios->getattr( 1 )\n\nReturns \"undef\" on failure.\n\n\"getcc\" Retrieve a value from the \"ccc\" field of a \"termios\" object. The \"ccc\" field is an\narray so an index must be specified.\n\n$ccc[1] = $termios->getcc(1);\n\n\"getcflag\"\nRetrieve the \"ccflag\" field of a \"termios\" object.\n\n$ccflag = $termios->getcflag;\n\n\"getiflag\"\nRetrieve the \"ciflag\" field of a \"termios\" object.\n\n$ciflag = $termios->getiflag;\n\n\"getispeed\"\nRetrieve the input baud rate.\n\n$ispeed = $termios->getispeed;\n\n\"getlflag\"\nRetrieve the \"clflag\" field of a \"termios\" object.\n\n$clflag = $termios->getlflag;\n\n\"getoflag\"\nRetrieve the \"coflag\" field of a \"termios\" object.\n\n$coflag = $termios->getoflag;\n\n\"getospeed\"\nRetrieve the output baud rate.\n\n$ospeed = $termios->getospeed;\n\n\"setattr\"\nSet terminal control attributes.\n\nSet attributes immediately for stdout.\n\n$termios->setattr( 1, &POSIX::TCSANOW );\n\nReturns \"undef\" on failure.\n\n\"setcc\" Set a value in the \"ccc\" field of a \"termios\" object. The \"ccc\" field is an array so\nan index must be specified.\n\n$termios->setcc( &POSIX::VEOF, 1 );\n\n\"setcflag\"\nSet the \"ccflag\" field of a \"termios\" object.\n\n$termios->setcflag( $ccflag | &POSIX::CLOCAL );\n\n\"setiflag\"\nSet the \"ciflag\" field of a \"termios\" object.\n\n$termios->setiflag( $ciflag | &POSIX::BRKINT );\n\n\"setispeed\"\nSet the input baud rate.\n\n$termios->setispeed( &POSIX::B9600 );\n\nReturns \"undef\" on failure.\n\n\"setlflag\"\nSet the \"clflag\" field of a \"termios\" object.\n\n$termios->setlflag( $clflag | &POSIX::ECHO );\n\n\"setoflag\"\nSet the \"coflag\" field of a \"termios\" object.\n\n$termios->setoflag( $coflag | &POSIX::OPOST );\n\n\"setospeed\"\nSet the output baud rate.\n\n$termios->setospeed( &POSIX::B9600 );\n\nReturns \"undef\" on failure.\n\nBaud rate values\n\"B38400\" \"B75\" \"B200\" \"B134\" \"B300\" \"B1800\" \"B150\" \"B0\" \"B19200\" \"B1200\" \"B9600\" \"B600\"\n\"B4800\" \"B50\" \"B2400\" \"B110\"\n\nTerminal interface values\n\"TCSADRAIN\" \"TCSANOW\" \"TCOON\" \"TCIOFLUSH\" \"TCOFLUSH\" \"TCION\" \"TCIFLUSH\" \"TCSAFLUSH\"\n\"TCIOFF\" \"TCOOFF\"\n\n\"ccc\" field values\n\"VEOF\" \"VEOL\" \"VERASE\" \"VINTR\" \"VKILL\" \"VQUIT\" \"VSUSP\" \"VSTART\" \"VSTOP\" \"VMIN\" \"VTIME\"\n\"NCCS\"\n\n\"ccflag\" field values\n\"CLOCAL\" \"CREAD\" \"CSIZE\" \"CS5\" \"CS6\" \"CS7\" \"CS8\" \"CSTOPB\" \"HUPCL\" \"PARENB\" \"PARODD\"\n\n\"ciflag\" field values\n\"BRKINT\" \"ICRNL\" \"IGNBRK\" \"IGNCR\" \"IGNPAR\" \"INLCR\" \"INPCK\" \"ISTRIP\" \"IXOFF\" \"IXON\"\n\"PARMRK\"\n\n\"clflag\" field values\n\"ECHO\" \"ECHOE\" \"ECHOK\" \"ECHONL\" \"ICANON\" \"IEXTEN\" \"ISIG\" \"NOFLSH\" \"TOSTOP\"\n\n\"coflag\" field values\n\"OPOST\"\n",
            "subsections": []
        },
        "PATHNAME CONSTANTS": {
            "content": "Constants\n\"PCCHOWNRESTRICTED\" \"PCLINKMAX\" \"PCMAXCANON\" \"PCMAXINPUT\" \"PCNAMEMAX\"\n\"PCNOTRUNC\" \"PCPATHMAX\" \"PCPIPEBUF\" \"PCVDISABLE\"\n",
            "subsections": []
        },
        "POSIX CONSTANTS": {
            "content": "Constants\n\"POSIXARGMAX\" \"POSIXCHILDMAX\" \"POSIXCHOWNRESTRICTED\" \"POSIXJOBCONTROL\"\n\"POSIXLINKMAX\" \"POSIXMAXCANON\" \"POSIXMAXINPUT\" \"POSIXNAMEMAX\"\n\"POSIXNGROUPSMAX\" \"POSIXNOTRUNC\" \"POSIXOPENMAX\" \"POSIXPATHMAX\"\n\"POSIXPIPEBUF\" \"POSIXSAVEDIDS\" \"POSIXSSIZEMAX\" \"POSIXSTREAMMAX\"\n\"POSIXTZNAMEMAX\" \"POSIXVDISABLE\" \"POSIXVERSION\"\n",
            "subsections": []
        },
        "RESOURCE CONSTANTS": {
            "content": "Imported with the \":sysresourceh\" tag.\n\nConstants\nAdded in Perl v5.28:\n\n\"PRIOPROCESS\" \"PRIOPGRP\" \"PRIOUSER\"\n",
            "subsections": []
        },
        "SYSTEM CONFIGURATION": {
            "content": "Constants\n\"SCARGMAX\" \"SCCHILDMAX\" \"SCCLKTCK\" \"SCJOBCONTROL\" \"SCNGROUPSMAX\"\n\"SCOPENMAX\" \"SCPAGESIZE\" \"SCSAVEDIDS\" \"SCSTREAMMAX\" \"SCTZNAMEMAX\"\n\"SCVERSION\"\n",
            "subsections": []
        },
        "ERRNO": {
            "content": "Constants\n\"E2BIG\" \"EACCES\" \"EADDRINUSE\" \"EADDRNOTAVAIL\" \"EAFNOSUPPORT\" \"EAGAIN\" \"EALREADY\" \"EBADF\"\n\"EBADMSG\" \"EBUSY\" \"ECANCELED\" \"ECHILD\" \"ECONNABORTED\" \"ECONNREFUSED\" \"ECONNRESET\"\n\"EDEADLK\" \"EDESTADDRREQ\" \"EDOM\" \"EDQUOT\" \"EEXIST\" \"EFAULT\" \"EFBIG\" \"EHOSTDOWN\"\n\"EHOSTUNREACH\" \"EIDRM\" \"EILSEQ\" \"EINPROGRESS\" \"EINTR\" \"EINVAL\" \"EIO\" \"EISCONN\" \"EISDIR\"\n\"ELOOP\" \"EMFILE\" \"EMLINK\" \"EMSGSIZE\" \"ENAMETOOLONG\" \"ENETDOWN\" \"ENETRESET\" \"ENETUNREACH\"\n\"ENFILE\" \"ENOBUFS\" \"ENODATA\" \"ENODEV\" \"ENOENT\" \"ENOEXEC\" \"ENOLCK\" \"ENOLINK\" \"ENOMEM\"\n\"ENOMSG\" \"ENOPROTOOPT\" \"ENOSPC\" \"ENOSR\" \"ENOSTR\" \"ENOSYS\" \"ENOTBLK\" \"ENOTCONN\" \"ENOTDIR\"\n\"ENOTEMPTY\" \"ENOTRECOVERABLE\" \"ENOTSOCK\" \"ENOTSUP\" \"ENOTTY\" \"ENXIO\" \"EOPNOTSUPP\"\n\"EOTHER\" \"EOVERFLOW\" \"EOWNERDEAD\" \"EPERM\" \"EPFNOSUPPORT\" \"EPIPE\" \"EPROCLIM\" \"EPROTO\"\n\"EPROTONOSUPPORT\" \"EPROTOTYPE\" \"ERANGE\" \"EREMOTE\" \"ERESTART\" \"EROFS\" \"ESHUTDOWN\"\n\"ESOCKTNOSUPPORT\" \"ESPIPE\" \"ESRCH\" \"ESTALE\" \"ETIME\" \"ETIMEDOUT\" \"ETOOMANYREFS\" \"ETXTBSY\"\n\"EUSERS\" \"EWOULDBLOCK\" \"EXDEV\"\n",
            "subsections": []
        },
        "FCNTL": {
            "content": "Constants\n\"FDCLOEXEC\" \"FDUPFD\" \"FGETFD\" \"FGETFL\" \"FGETLK\" \"FOK\" \"FRDLCK\" \"FSETFD\"\n\"FSETFL\" \"FSETLK\" \"FSETLKW\" \"FUNLCK\" \"FWRLCK\" \"OACCMODE\" \"OAPPEND\" \"OCREAT\"\n\"OEXCL\" \"ONOCTTY\" \"ONONBLOCK\" \"ORDONLY\" \"ORDWR\" \"OTRUNC\" \"OWRONLY\"\n",
            "subsections": []
        },
        "FLOAT": {
            "content": "Constants\n\"DBLDIG\" \"DBLEPSILON\" \"DBLMANTDIG\" \"DBLMAX\" \"DBLMAX10EXP\" \"DBLMAXEXP\"\n\"DBLMIN\" \"DBLMIN10EXP\" \"DBLMINEXP\" \"FLTDIG\" \"FLTEPSILON\" \"FLTMANTDIG\"\n\"FLTMAX\" \"FLTMAX10EXP\" \"FLTMAXEXP\" \"FLTMIN\" \"FLTMIN10EXP\" \"FLTMINEXP\"\n\"FLTRADIX\" \"FLTROUNDS\" \"LDBLDIG\" \"LDBLEPSILON\" \"LDBLMANTDIG\" \"LDBLMAX\"\n\"LDBLMAX10EXP\" \"LDBLMAXEXP\" \"LDBLMIN\" \"LDBLMIN10EXP\" \"LDBLMINEXP\"\n",
            "subsections": []
        },
        "FLOATING-POINT ENVIRONMENT": {
            "content": "Constants\n\"FEDOWNWARD\" \"FETONEAREST\" \"FETOWARDZERO\" \"FEUPWARD\" on systems that support them.\n",
            "subsections": []
        },
        "LIMITS": {
            "content": "Constants\n\"ARGMAX\" \"CHARBIT\" \"CHARMAX\" \"CHARMIN\" \"CHILDMAX\" \"INTMAX\" \"INTMIN\" \"LINKMAX\"\n\"LONGMAX\" \"LONGMIN\" \"MAXCANON\" \"MAXINPUT\" \"MBLENMAX\" \"NAMEMAX\" \"NGROUPSMAX\"\n\"OPENMAX\" \"PATHMAX\" \"PIPEBUF\" \"SCHARMAX\" \"SCHARMIN\" \"SHRTMAX\" \"SHRTMIN\"\n\"SSIZEMAX\" \"STREAMMAX\" \"TZNAMEMAX\" \"UCHARMAX\" \"UINTMAX\" \"ULONGMAX\" \"USHRTMAX\"\n",
            "subsections": []
        },
        "LOCALE": {
            "content": "Constants\n\"LCALL\" \"LCCOLLATE\" \"LCCTYPE\" \"LCMONETARY\" \"LCNUMERIC\" \"LCTIME\" \"LCMESSAGES\" on\nsystems that support them.\n",
            "subsections": []
        },
        "MATH": {
            "content": "Constants\n\"HUGEVAL\"\n\nAdded in Perl v5.22:\n\n\"FPILOGB0\" \"FPILOGBNAN\" \"FPINFINITE\" \"FPNAN\" \"FPNORMAL\" \"FPSUBNORMAL\" \"FPZERO\"\n\"INFINITY\" \"NAN\" \"Inf\" \"NaN\" \"M1PI\" \"M2PI\" \"M2SQRTPI\" \"ME\" \"MLN10\" \"MLN2\"\n\"MLOG10E\" \"MLOG2E\" \"MPI\" \"MPI2\" \"MPI4\" \"MSQRT12\" \"MSQRT2\" on systems with C99\nsupport.\n",
            "subsections": []
        },
        "SIGNAL": {
            "content": "Constants\n\"SANOCLDSTOP\" \"SANOCLDWAIT\" \"SANODEFER\" \"SAONSTACK\" \"SARESETHAND\" \"SARESTART\"\n\"SASIGINFO\" \"SIGABRT\" \"SIGALRM\" \"SIGCHLD\" \"SIGCONT\" \"SIGFPE\" \"SIGHUP\" \"SIGILL\" \"SIGINT\"\n\"SIGKILL\" \"SIGPIPE\" \"SIGQUIT\" \"SIGSEGV\" \"SIGSTOP\" \"SIGTERM\" \"SIGTSTP\" \"SIGTTIN\"\n\"SIGTTOU\" \"SIGUSR1\" \"SIGUSR2\" \"SIGBLOCK\" \"SIGDFL\" \"SIGERR\" \"SIGIGN\" \"SIGSETMASK\"\n\"SIGUNBLOCK\"\n\nAdded in Perl v5.24:\n\n\"ILLILLOPC\" \"ILLILLOPN\" \"ILLILLADR\" \"ILLILLTRP\" \"ILLPRVOPC\" \"ILLPRVREG\"\n\"ILLCOPROC\" \"ILLBADSTK\" \"FPEINTDIV\" \"FPEINTOVF\" \"FPEFLTDIV\" \"FPEFLTOVF\"\n\"FPEFLTUND\" \"FPEFLTRES\" \"FPEFLTINV\" \"FPEFLTSUB\" \"SEGVMAPERR\" \"SEGVACCERR\"\n\"BUSADRALN\" \"BUSADRERR\" \"BUSOBJERR\" \"TRAPBRKPT\" \"TRAPTRACE\" \"CLDEXITED\"\n\"CLDKILLED\" \"CLDDUMPED\" \"CLDTRAPPED\" \"CLDSTOPPED\" \"CLDCONTINUED\" \"POLLIN\"\n\"POLLOUT\" \"POLLMSG\" \"POLLERR\" \"POLLPRI\" \"POLLHUP\" \"SIUSER\" \"SIQUEUE\" \"SITIMER\"\n\"SIASYNCIO\" \"SIMESGQ\"\n",
            "subsections": []
        },
        "STAT": {
            "content": "Constants\n\"SIRGRP\" \"SIROTH\" \"SIRUSR\" \"SIRWXG\" \"SIRWXO\" \"SIRWXU\" \"SISGID\" \"SISUID\"\n\"SIWGRP\" \"SIWOTH\" \"SIWUSR\" \"SIXGRP\" \"SIXOTH\" \"SIXUSR\"\n\nMacros  \"SISBLK\" \"SISCHR\" \"SISDIR\" \"SISFIFO\" \"SISLNK\" \"SISREG\" \"SISSOCK\"\n",
            "subsections": []
        },
        "STDLIB": {
            "content": "Constants\n\"EXITFAILURE\" \"EXITSUCCESS\" \"MBCURMAX\" \"RANDMAX\"\n",
            "subsections": []
        },
        "STDIO": {
            "content": "Constants\n\"BUFSIZ\" \"EOF\" \"FILENAMEMAX\" \"Lctermid\" \"Lcuserid\" \"TMPMAX\"\n",
            "subsections": []
        },
        "TIME": {
            "content": "Constants\n\"CLKTCK\" \"CLOCKSPERSEC\"\n",
            "subsections": []
        },
        "UNISTD": {
            "content": "Constants\n\"ROK\" \"SEEKCUR\" \"SEEKEND\" \"SEEKSET\" \"STDINFILENO\" \"STDOUTFILENO\" \"STDERRFILENO\"\n\"WOK\" \"XOK\"\n",
            "subsections": []
        },
        "WAIT": {
            "content": "Constants\n\"WNOHANG\" \"WUNTRACED\"\n\n\"WNOHANG\"       Do not suspend the calling process until a child process changes state\nbut instead return immediately.\n\n\"WUNTRACED\"     Catch stopped child processes.\n\nMacros  \"WIFEXITED\" \"WEXITSTATUS\" \"WIFSIGNALED\" \"WTERMSIG\" \"WIFSTOPPED\" \"WSTOPSIG\"\n\n\"WIFEXITED\"     WIFEXITED(${^CHILDERRORNATIVE}) returns true if the child process\nexited normally (exit() or by falling off the end of main())\n\n\"WEXITSTATUS\"   WEXITSTATUS(${^CHILDERRORNATIVE}) returns the normal exit status of\nthe child process (only meaningful if WIFEXITED(${^CHILDERRORNATIVE})\nis true)\n\n\"WIFSIGNALED\"   WIFSIGNALED(${^CHILDERRORNATIVE}) returns true if the child process\nterminated because of a signal\n\n\"WTERMSIG\"      WTERMSIG(${^CHILDERRORNATIVE}) returns the signal the child process\nterminated for (only meaningful if WIFSIGNALED(${^CHILDERRORNATIVE})\nis true)\n\n\"WIFSTOPPED\"    WIFSTOPPED(${^CHILDERRORNATIVE}) returns true if the child process is\ncurrently stopped (can happen only if you specified the WUNTRACED flag\nto waitpid())\n\n\"WSTOPSIG\"      WSTOPSIG(${^CHILDERRORNATIVE}) returns the signal the child process\nwas stopped for (only meaningful if WIFSTOPPED(${^CHILDERRORNATIVE})\nis true)\n",
            "subsections": []
        },
        "WINSOCK": {
            "content": "(Windows only.)\n\nConstants\nAdded in Perl v5.24:\n\n\"WSAEINTR\" \"WSAEBADF\" \"WSAEACCES\" \"WSAEFAULT\" \"WSAEINVAL\" \"WSAEMFILE\" \"WSAEWOULDBLOCK\"\n\"WSAEINPROGRESS\" \"WSAEALREADY\" \"WSAENOTSOCK\" \"WSAEDESTADDRREQ\" \"WSAEMSGSIZE\"\n\"WSAEPROTOTYPE\" \"WSAENOPROTOOPT\" \"WSAEPROTONOSUPPORT\" \"WSAESOCKTNOSUPPORT\"\n\"WSAEOPNOTSUPP\" \"WSAEPFNOSUPPORT\" \"WSAEAFNOSUPPORT\" \"WSAEADDRINUSE\" \"WSAEADDRNOTAVAIL\"\n\"WSAENETDOWN\" \"WSAENETUNREACH\" \"WSAENETRESET\" \"WSAECONNABORTED\" \"WSAECONNRESET\"\n\"WSAENOBUFS\" \"WSAEISCONN\" \"WSAENOTCONN\" \"WSAESHUTDOWN\" \"WSAETOOMANYREFS\" \"WSAETIMEDOUT\"\n\"WSAECONNREFUSED\" \"WSAELOOP\" \"WSAENAMETOOLONG\" \"WSAEHOSTDOWN\" \"WSAEHOSTUNREACH\"\n\"WSAENOTEMPTY\" \"WSAEPROCLIM\" \"WSAEUSERS\" \"WSAEDQUOT\" \"WSAESTALE\" \"WSAEREMOTE\"\n\"WSAEDISCON\" \"WSAENOMORE\" \"WSAECANCELLED\" \"WSAEINVALIDPROCTABLE\" \"WSAEINVALIDPROVIDER\"\n\"WSAEPROVIDERFAILEDINIT\" \"WSAEREFUSED\"\n",
            "subsections": []
        }
    },
    "summary": "POSIX - Perl interface to IEEE Std 1003.1",
    "flags": [],
    "examples": [],
    "see_also": []
}