| GETGROUPS(2) | System Calls Manual | GETGROUPS(2) |
getgroups — get
group access list
Standard C Library (libc, -lc)
#include
<unistd.h>
int
getgroups(int
gidsetlen, gid_t
*gidset);
The
getgroups()
system call gets the current group access list of the user process and
stores it in the array gidset. The
gidsetlen argument indicates the number of entries
that may be placed in gidset. The
getgroups() system call returns the actual number of
groups returned in gidset. At least one and as many as
{NGROUPS_MAX}+1 values may be returned. If gidsetlen
is zero, getgroups() returns the number of
supplementary group IDs associated with the calling process without
modifying the array pointed to by gidset.
The value of {NGROUPS_MAX} should be
obtained using sysconf(3) to avoid hard-coding it into the
executable.
A successful call returns the number of groups in the group set. A value of -1 indicates that an error occurred, and the error code is stored in the global variable errno.
The possible errors for getgroups()
are:
The getgroups() system call conforms to
IEEE Std 1003.1-2008 (“POSIX.1”).
The getgroups() system call appeared in
4.2BSD.
| January 21, 2011 | Debian |