NAME

getgroups - get supplementary group IDs

 SYNOPSIS

#include <sys/types.h>
#include <unistd.h>

int getgroups(int gidsetsize, gid_t grouplist[]);

 DESCRIPTION

The getgroups() function fills in the array grouplist with the current supplementary group IDs of the calling process.

The gidsetsize argument specifies the number of elements in the array grouplist. The actual number of supplementary group IDs stored in the array is returned. The values of array entries with indices greater than or equal to the value returned are undefined.

If gidsetsize is 0, getgroups() returns the number of supplementary group IDs associated with the calling process without modifying the array pointed to by grouplist.

It is unspecified whether the effective group ID of the calling process is included in, or omitted from, the returned list of supplementary group IDs.

 RETURN VALUE

Upon successful completion, the number of supplementary group IDs is returned. A return value of -1 indicates failure and errno is set to indicate the error.

 ERRORS

The getgroups() function will fail if:

[EINVAL]

The gidsetsize argument is non-zero and is less than the number of supplementary group IDs.

 EXAMPLES

None.

 APPLICATION USAGE

None.

 FUTURE DIRECTIONS

None.

 SEE ALSO

getegid(), setgid(), <sys/types.h>, <unistd.h>.

DERIVATION

Derived from the POSIX.1-1988 standard.