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GETGROUPS
!!!GETGROUPS
NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
NOTES
CONFORMING TO
SEE ALSO
----
!!NAME


getgroups, setgroups - get/set list of supplementary group IDs
!!SYNOPSIS


__#include __
#include __


__int getgroups(int__ ''size''__, gid_t__
''list''__[[]);__


__#include __


__int setgroups(size_t__ ''size''__, const gid_t
*__''list''__);__
!!DESCRIPTION


__getgroups__


Up to ''size'' supplementary group IDs are returned in
''list''. It is unspecified whether the effective group
ID of the calling process is included in the returned list.
(Thus, an application should also call getegid(2) and
add or remove the resulting value.) If ''size'' is zero,
''list'' is not modified, but the total number of
supplementary group IDs for the process is
returned.


__setgroups__


Sets the supplementary group IDs for the process. Only the
super-user may use this function.
!!RETURN VALUE


__getgroups__


On success, the number of supplementary group IDs is
returned. On error, -1 is returned, and ''errno'' is set
appropriately.


__setgroups__


On success, zero is returned. On error, -1 is returned, and
''errno'' is set appropriately.
!!ERRORS


__EFAULT__


''list'' has an invalid address.


__EPERM__


For __setgroups__, the user is not the
super-user.


__EINVAL__


For __setgroups__, ''size'' is greater than
__NGROUPS__ (32 for Linux 2.0.32). For __getgroups__,
''size'' is less than the number of supplementary group
IDs, but is not zero.
!!NOTES


A process can have up to at least NGROUPS_MAX supplementary
group IDs in addition to the effective group ID. The set of
supplementary group IDs is inherited from the parent process
and may be changed using __setgroups__. The maximum
number of supplementary group IDs can be found using
sysconf(3):


    long ngroups_max;
ngroups_max = sysconf(_SC_NGROUPS_MAX);
The maximal return value of __getgroups__ cannot be larger than one more than the value obtained this way.


The prototype for __setgroups__ is only available if
___BSD_SOURCE__ is defined (either explicitly, or
implicitly, by not defining _POSIX_SOURCE or compiling with
the -ansi flag).
!!CONFORMING TO


SVr4, SVID (issue 4 only; these calls were not present in
SVr3), X/OPEN, 4.3BSD. The __getgroups__ function is in
POSIX.1. Since __setgroups__ requires privilege, it is
not covered by POSIX.1.
!!SEE ALSO


initgroups(3), getgid(2),
setgid(2)
----

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Last edited on Tuesday, June 4, 2002 12:23:41 am by "perry"

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