GETGROUPLIST(3) BSD Programmer's Manual GETGROUPLIST(3)
getgrouplist - calculate group access list
getgrouplist(const char *name, int basegid, int *groups, int *ngroups);
The getgrouplist() function reads through the group file and calculates
the group access list for the user specified in name. The basegid is au-
tomatically included in the groups list. Typically this value is given
as the group number from the password file.
The resulting group list is returned in the integer array pointed to by
groups. The caller specifies the size of the groups array in the integer
pointed to by ngroups; the actual number of groups found is returned in
The getgrouplist() function returns -1 if the size of the group list is
too small to hold all the user's groups. Here, the group array will be
filled with as many groups as will fit.
/etc/group group membership list
The getgrouplist() function first appeared in 4.4BSD.
The getgrouplist() function uses the routines based on getgrent(3). If
the invoking program uses any of these routines, the group structure will
be overwritten in the call to getgrouplist().
4.4BSD June 9, 1993 1