getgroups(2)                     UNIX System V                     getgroups(2)


NAME
      getgroups, setgroups - get or set supplementary group access list IDs

SYNOPSIS
      #include <unistd.h>

      int getgroups(int gidsetsize, gidt *grouplist)

      int setgroups(int ngroups, const gidt *grouplist)

DESCRIPTION
      getgroups gets the current supplemental group access list of the calling
      process and stores the result in the array of group IDs specified by
      grouplist.  This array has gidsetsize entries and must be large enough to
      contain the entire list.  This list cannot be greater than {NGOUPSMAX}.
      If gidsetsize equals 0, getgroups will return the number of groups to
      which the calling process belongs without modifying the array pointed to
      by grouplist.

      setgroups sets the supplementary group access list of the calling process
      from the array of group IDs specified by grouplist.  The number of
      entries is specified by ngroups and can not be greater than
      {NGROUPSMAX}.  This function may be invoked only by the super-user.

      getgroups will fail if:

      EINVAL         The value of gidsetsize is non-zero and less than the
                     number of supplementary group IDs set for the calling
                     process.

      setgroups will fail if:

      EINVAL         The value of ngroups is greater than {NGROUPSMAX}.

      EPERM          The effective user ID is not super-user.

      Either call will fail if:

      EFAULT         A referenced part of the array pointed to by grouplist is
                     outside of the allocated address space of the process.

SEE ALSO
      chown(2), getuid(2), setuid(2), initgroups(3C).
      groups(1) in the User's Reference Manual.

DIAGNOSTICS
      Upon successful completion, getgroups returns the number of supplementary
      group IDs set for the calling process and setgroups returns the value 0.
      Otherwise, a value of -1 is returned and errno is set to indicate the
      error.




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