{
    "mode": "perldoc",
    "parameter": "Fcntl",
    "section": "",
    "url": "https://www.chedong.com/phpMan.php/perldoc/Fcntl/json",
    "generated": "2026-07-05T13:36:54Z",
    "synopsis": "use Fcntl;\nuse Fcntl qw(:DEFAULT :flock);",
    "sections": {
        "NAME": {
            "content": "Fcntl - load the C Fcntl.h defines\n",
            "subsections": []
        },
        "SYNOPSIS": {
            "content": "use Fcntl;\nuse Fcntl qw(:DEFAULT :flock);\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "This module is just a translation of the C fcntl.h file. Unlike the old mechanism of requiring a\ntranslated fcntl.ph file, this uses the h2xs program (see the Perl source distribution) and your\nnative C compiler. This means that it has a far more likely chance of getting the numbers right.\n",
            "subsections": []
        },
        "NOTE": {
            "content": "Only \"#define\" symbols get translated; you must still correctly pack up your own arguments to\npass as args for locking functions, etc.\n",
            "subsections": []
        },
        "EXPORTED SYMBOLS": {
            "content": "By default your system's F* and O* constants (eg, FDUPFD and OCREAT) and the FDCLOEXEC\nconstant are exported into your namespace.\n\nYou can request that the flock() constants (LOCKSH, LOCKEX, LOCKNB and LOCKUN) be provided\nby using the tag \":flock\". See Exporter.\n\nYou can request that the old constants (FAPPEND, FASYNC, FCREAT, FDEFER, FEXCL, FNDELAY,\nFNONBLOCK, FSYNC, FTRUNC) be provided for compatibility reasons by using the tag \":Fcompat\". For\nnew applications the newer versions of these constants are suggested (OAPPEND, OASYNC,\nOCREAT, ODEFER, OEXCL, ONDELAY, ONONBLOCK, OSYNC, OTRUNC).\n\nFor ease of use also the SEEK* constants (for seek() and sysseek(), e.g. SEEKEND) and the SI*\nconstants (for chmod() and stat()) are available for import. They can be imported either\nseparately or using the tags \":seek\" and \":mode\".\n\nPlease refer to your native fcntl(2), open(2), fseek(3), lseek(2) (equal to Perl's seek() and",
            "subsections": [
                {
                    "name": "sysseek",
                    "content": "your system.\n\nSee perlopentut to learn about the uses of the O* constants with sysopen().\n\nSee \"seek\" in perlfunc and \"sysseek\" in perlfunc about the SEEK* constants.\n\nSee \"stat\" in perlfunc about the SI* constants.\n"
                }
            ]
        }
    },
    "summary": "Fcntl - load the C Fcntl.h defines",
    "flags": [],
    "examples": [],
    "see_also": []
}