{
    "mode": "man",
    "parameter": "intro",
    "section": "3",
    "url": "https://www.chedong.com/phpMan.php/man/intro/3/json",
    "generated": "2026-06-03T12:14:56Z",
    "sections": {
        "NAME": {
            "content": "intro - introduction to library functions\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "Section 3 of the manual describes all library functions excluding the library functions (sys‐\ntem call wrappers) described in Section 2, which implement system calls.\n\nMany of the functions described in the section are part of the  Standard  C  Library  (libc).\nSome  functions  are  part of other libraries (e.g., the math library, libm, or the real-time\nlibrary, librt) in which case the manual page will indicate the linker option needed to  link\nagainst  the  required  library (e.g., -lm and -lrt, respectively, for the aforementioned li‐\nbraries).\n\nIn some cases, the programmer must define a feature test macro in order to obtain the  decla‐\nration of a function from the header file specified in the man page SYNOPSIS section.  (Where\nrequired, these feature test macros must be defined before including any header  files.)   In\nsuch cases, the required macro is described in the man page.  For further information on fea‐\nture test macros, see featuretestmacros(7).\n",
            "subsections": []
        },
        "CONFORMING TO": {
            "content": "Certain terms and abbreviations are used to indicate UNIX variants  and  standards  to  which\ncalls in this section conform.  See standards(7).\n",
            "subsections": []
        },
        "NOTES": {
            "content": "",
            "subsections": [
                {
                    "name": "Authors and copyright conditions",
                    "content": "Look  at  the  header  of  the manual page source for the author(s) and copyright conditions.\nNote that these can be different from page to page!\n"
                }
            ]
        },
        "SEE ALSO": {
            "content": "intro(2),  errno(3),  capabilities(7),  credentials(7),  environ(7),  featuretestmacros(7),\nlibc(7),   matherror(7),  pathresolution(7),  pthreads(7),  signal(7),  standards(7),  sys‐‐\ntemdatatypes(7)\n",
            "subsections": []
        },
        "COLOPHON": {
            "content": "This page is part of release 5.10 of the Linux  man-pages  project.   A  description  of  the\nproject,  information about reporting bugs, and the latest version of this page, can be found\nat https://www.kernel.org/doc/man-pages/.\n\n\n\nLinux                                        2020-11-01                                     INTRO(3)",
            "subsections": []
        }
    },
    "summary": "intro - introduction to library functions",
    "flags": [],
    "examples": [],
    "see_also": [
        {
            "name": "errno",
            "section": "3",
            "url": "https://www.chedong.com/phpMan.php/man/errno/3/json"
        },
        {
            "name": "capabilities",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/capabilities/7/json"
        },
        {
            "name": "credentials",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/credentials/7/json"
        },
        {
            "name": "environ",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/environ/7/json"
        },
        {
            "name": "featuretestmacros",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/featuretestmacros/7/json"
        },
        {
            "name": "libc",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/libc/7/json"
        },
        {
            "name": "matherror",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/matherror/7/json"
        },
        {
            "name": "pathresolution",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/pathresolution/7/json"
        },
        {
            "name": "pthreads",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/pthreads/7/json"
        },
        {
            "name": "signal",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/signal/7/json"
        },
        {
            "name": "standards",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/standards/7/json"
        },
        {
            "name": "temdatatypes",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/temdatatypes/7/json"
        }
    ]
}