{
    "mode": "man",
    "parameter": "libc",
    "section": "7",
    "url": "https://www.chedong.com/phpMan.php/man/libc/7/json",
    "generated": "2026-05-30T05:14:22Z",
    "sections": {
        "NAME": {
            "content": "libc - overview of standard C libraries on Linux\n",
            "subsections": []
        },
        "DESCRIPTION": {
            "content": "The  term  \"libc\"  is commonly used as a shorthand for the \"standard C library\", a library of\nstandard functions that can be used by all C programs (and sometimes  by  programs  in  other\nlanguages).   Because  of  some  history  (see below), use of the term \"libc\" to refer to the\nstandard C library is somewhat ambiguous on Linux.\n",
            "subsections": [
                {
                    "name": "glibc",
                    "content": "By far the most widely used C library on Linux  is  the  GNU  C  Library  ⟨http://www.gnu.org\n/software/libc/⟩, often referred to as glibc.  This is the C library that is nowadays used in\nall major Linux distributions.  It is also the C library whose details are documented in  the\nrelevant  pages  of the man-pages project (primarily in Section 3 of the manual).  Documenta‐\ntion of glibc is also available in the glibc manual, available via  the  command  info  libc.\nRelease  1.0  of  glibc  was made in September 1992.  (There were earlier 0.x releases.)  The\nnext major release of glibc was 2.0, at the beginning of 1997.\n\nThe pathname /lib/libc.so.6 (or something similar) is normally a symbolic link that points to\nthe  location  of  the glibc library, and executing this pathname will cause glibc to display\nvarious information about the version installed on your system.\n"
                },
                {
                    "name": "Linux libc",
                    "content": "In the early to mid 1990s, there was for a while Linux libc, a fork of glibc 1.x  created  by\nLinux  developers who felt that glibc development at the time was not sufficing for the needs\nof Linux.  Often, this library was referred to (ambiguously) as just \"libc\".  Linux libc  re‐\nleased  major  versions  2,  3,  4,  and 5, as well as many minor versions of those releases.\nLinux libc4 was the last version to use the a.out binary format, and  the  first  version  to\nprovide  (primitive)  shared  library support.  Linux libc 5 was the first version to support\nthe ELF binary format; this version used the shared library soname libc.so.5.  For  a  while,\nLinux libc was the standard C library in many Linux distributions.\n\nHowever, notwithstanding the original motivations of the Linux libc effort, by the time glibc\n2.0 was released (in 1997), it was clearly superior to Linux libc, and all major  Linux  dis‐\ntributions  that  had been using Linux libc soon switched back to glibc.  To avoid any confu‐\nsion with Linux libc versions, glibc 2.0 and later used the shared library soname libc.so.6.\n\nSince the switch from Linux libc to glibc 2.0 occurred long ago, man-pages  no  longer  takes\ncare to document Linux libc details.  Nevertheless, the history is visible in vestiges of in‐\nformation about Linux libc that remain in a few manual pages, in  particular,  references  to\nlibc4 and libc5.\n"
                },
                {
                    "name": "Other C libraries",
                    "content": "There  are  various other less widely used C libraries for Linux.  These libraries are gener‐\nally smaller than glibc, both in terms of features and memory footprint, and  often  intended\nfor  building  small  binaries,  perhaps  targeted at development for embedded Linux systems.\nAmong     such     libraries     are      uClibc      ⟨http://www.uclibc.org/⟩,      dietlibc\n⟨http://www.fefe.de/dietlibc/⟩,  and musl libc ⟨http://www.musl-libc.org/⟩.  Details of these\nlibraries are covered by the man-pages project, where they are known.\n"
                }
            ]
        },
        "SEE ALSO": {
            "content": "syscalls(2),  getauxval(3),  proc(5),  featuretestmacros(7),  man-pages(7),   standards(7),\nvdso(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                                        2016-12-12                                      LIBC(7)",
            "subsections": []
        }
    },
    "summary": "libc - overview of standard C libraries on Linux",
    "flags": [],
    "examples": [],
    "see_also": [
        {
            "name": "syscalls",
            "section": "2",
            "url": "https://www.chedong.com/phpMan.php/man/syscalls/2/json"
        },
        {
            "name": "getauxval",
            "section": "3",
            "url": "https://www.chedong.com/phpMan.php/man/getauxval/3/json"
        },
        {
            "name": "proc",
            "section": "5",
            "url": "https://www.chedong.com/phpMan.php/man/proc/5/json"
        },
        {
            "name": "featuretestmacros",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/featuretestmacros/7/json"
        },
        {
            "name": "man-pages",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/man-pages/7/json"
        },
        {
            "name": "standards",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/standards/7/json"
        },
        {
            "name": "vdso",
            "section": "7",
            "url": "https://www.chedong.com/phpMan.php/man/vdso/7/json"
        }
    ]
}