INITGROUPS(3) BSD Library Functions Manual INITGROUPS(3)NAME
initgroups -- initialize supplementary group IDs
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
int
initgroups(const char *name, gid_t basegid);
DESCRIPTION
The initgroups() function uses the getgrouplist(3) function to calculate the supplementary group IDs for the user specified in name. This
group list is then set up for the current process using setgroups(2). The basegid is automatically included in the group list. Typically
this value is given as the group number from the password file.
If the groups database lists more than NGROUPS groups for name (including one for basegid), the later groups are ignored.
RETURN VALUES
The initgroups() function returns -1 if it was not invoked by the super-user.
SEE ALSO setgroups(2), getgrouplist(3)HISTORY
The initgroups() function appeared in 4.2BSD.
BUGS
The getgrouplist() function called by initgroups() uses the routines based on getgrent(3). If the invoking program uses any of these rou-
tines, the group structure will be overwritten in the call to initgroups().
BSD August 10, 2002 BSD
Check Out this Related Man Page
GETGROUPLIST(3) BSD Library Functions Manual GETGROUPLIST(3)NAME
getgrouplist, getgroupmembership, -- calculate group access list
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <unistd.h>
int
getgrouplist(const char *name, gid_t basegid, gid_t *groups, int *ngroups);
int
getgroupmembership(const char *name, gid_t basegid, gid_t *groups, int maxgrp, int *ngroups);
DESCRIPTION
The getgrouplist() and getgroupmembership() functions read through the group database and calculate the group access list for the user speci-
fied in name. The basegid is automatically included in the groups list. Typically this value is given as the group number from the password
database.
The resulting group list is returned in the integer array pointed to by groups.
For getgrouplist(), the caller specifies the size of the groups array in the integer pointed to by ngroups.
For getgroupmembership(), the caller specifies the size of the groups array in maxgrp.
The actual number of groups found is returned in ngroups.
Duplicate group ids will be suppressed from the result.
RETURN VALUES
The getgrouplist() and getgroupmembership() functions return 0 if successful, and return -1 if the size of the group list is too small to
hold all the user's groups. In the latter case, the groups array will be filled with as many groups as will fit and ngroups will contain the
total number of groups found.
FILES
/etc/group group membership list
SEE ALSO setgroups(2), initgroups(3), group(5)HISTORY
The getgrouplist() function first appeared in 4.4BSD. The getgroupmembership() function first appeared in NetBSD 3.0 to address an API defi-
ciency in getgrouplist().
BUGS
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().
BSD January 6, 2005 BSD