NAME
getgroups — get group access list
SYNOPSIS
#include <unistd.h>
int getgroups(int ngroups, gid_t gidset[]);
DESCRIPTION
getgroups()
gets the current group access list of the user process
and stores it in the array
gidset.
The parameter
ngroups
indicates the number of entries which may be placed in
gidset.
As a special case, if the
ngroups
argument is zero,
getgroups()
returns the number of group entries for the process.
In this case, the array pointed to by the
gidset
argument is not modified.
EXAMPLES
The following call to
getgroups()
(see
getgroups(2))
retrieves the group access list of the calling process
and stores the group ids in array mygidset:
int ngroups, ngroups_max;
gid_t *mygidset;
ngroups_max = (int) sysconf(_SC_NGROUPS_MAX);
mygidset = (gid_t *) malloc(sizeof(gid_t) * ngroups_max);
ngroups = getgroups(ngroups_max, mygidset);
RETURN VALUE
If successful,
getgroups()
returns a non-negative value indicating the number of elements returned in
gidset.
If an error occurs, a value of -1 is returned and
errno
is set to indicate the type of error.
ERRORS
getgroups()
fails if any of the following conditions are encountered:
- EFAULT
gidset
specifies an invalid address.
The reliable detection of this error is implementation dependent.
- EINVAL
The argument
ngroups
is not zero and is less than the number of groups in the
current group access list of the process.
AUTHOR
getgroups()
was developed by
HP and the University of California, Berkeley.
STANDARDS CONFORMANCE
getgroups(): AES, SVID3, XPG3, XPG4, FIPS 151-2, POSIX.1
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