initgroups(3) - Linux manual page (original) (raw)

initgroups(3) Library Functions Manual initgroups(3)

NAME top

   initgroups - initialize the supplementary group access list

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#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 top

   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 top

   The **initgroups**() function returns 0 on success.  On error, -1 is
   returned, and _[errno](../man3/errno.3.html)_ is set to indicate the error.

ERRORS top

   **ENOMEM** Insufficient memory to allocate group information
          structure.

   **EPERM** The calling process has insufficient privilege.  See the
          underlying system call [setgroups(2)](../man2/setgroups.2.html).

FILES top

   _/etc/group_
          group database file

ATTRIBUTES top

   For an explanation of the terms used in this section, see
   [attributes(7)](../man7/attributes.7.html).
   ┌───────────────────────────────┬───────────────┬────────────────┐
   │ **Interface** │ **Attribute** │ **Value** │
   ├───────────────────────────────┼───────────────┼────────────────┤
   │ **initgroups**()                  │ Thread safety │ MT-Safe locale │
   └───────────────────────────────┴───────────────┴────────────────┘

STANDARDS top

   None.

HISTORY top

   SVr4, 4.3BSD.

SEE ALSO top

   [getgroups(2)](../man2/getgroups.2.html), [setgroups(2)](../man2/setgroups.2.html), [credentials(7)](../man7/credentials.7.html)

COLOPHON top

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Linux man-pages 6.10 2024-07-23 initgroups(3)

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