initgroups(3) — Linux manual page

initgroups(3)           Library Functions Manual           initgroups(3)

NAME

       initgroups - initialize the supplementary group access list

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <sys/types.h>
       #include <grp.h>

       int initgroups(const char *user, gid_t group);

   Feature Test Macro Requirements for glibc (see
   feature_test_macros(7)):

       initgroups():
           Since glibc 2.19:
               _DEFAULT_SOURCE
           glibc 2.19 and earlier:
               _BSD_SOURCE

DESCRIPTION

       The initgroups() function initializes the group access list by
       reading the group database /etc/group and using all groups of
       which user is a member.  The additional group group is also added
       to the list.

       The user argument must be non-NULL.

RETURN VALUE

       The initgroups() function returns 0 on success.  On error, -1 is
       returned, and errno is set to indicate the error.

ERRORS

       ENOMEM Insufficient memory to allocate group information
              structure.

       EPERM  The calling process has insufficient privilege.  See the
              underlying system call setgroups(2).

FILES

       /etc/group
              group database file

ATTRIBUTES

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌──────────────────────────────┬───────────────┬────────────────┐
       │ Interface                    │ Attribute     │ Value          │
       ├──────────────────────────────┼───────────────┼────────────────┤
       │ initgroups()                 │ Thread safety │ MT-Safe locale │
       └──────────────────────────────┴───────────────┴────────────────┘

STANDARDS

       None.

HISTORY

       SVr4, 4.3BSD.

SEE ALSO

       getgroups(2), setgroups(2), credentials(7)

COLOPHON

       This page is part of the man-pages (Linux kernel and C library
       user-space interface documentation) project.  Information about
       the project can be found at 
       ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report
       for this manual page, see
       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
       This page was obtained from the tarball man-pages-6.9.1.tar.gz
       fetched from
       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
       2024-06-26.  If you discover any rendering problems in this HTML
       version of the page, or you believe there is a better or more up-
       to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not
       part of the original manual page), send a mail to
       man-pages@man7.org

Linux man-pages 6.9.1          2024-05-02                  initgroups(3)

Pages that refer to this page: groups(1@@shadow-utils), getgroups(2), group(5), nss(5), credentials(7)

---