getgroups(2) System Calls Manual getgroups(2)
getgroups - get group access list
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, returns the number of group entries for the process. In this case, the array pointed
to by the gidset argument is not modified.
The following call to (see getgroups(2)) retrieves the group access list of the calling process and stores the group ids in array mygidset:
If successful, returns a non-negative value indicating the number of elements returned in gidset. If an error occurs, a value of -1 is
returned and is set to indicate the type of error.
fails if any of the following conditions are encountered:
gidset specifies an invalid address. The reliable detection of this error is implementation dependent.
The argument ngroups is not zero and is less than the number of groups in the current group access list of the process.
was developed by HP and the University of California, Berkeley.
setgroups(2), sysconf(2), initgroups(3C).