freebsd man page for initgroups

INITGROUPS(3)						   BSD Library Functions Manual 					     INITGROUPS(3)

NAME
     initgroups -- initialize group access list

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 group access list for the user specified in name.  This group
     list is then setup for the current process using setgroups(2).  The basegid is automatically included in the groups list.	Typically this
     value is given as the group number from the password file.

RETURN VALUES
     The initgroups() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indi-
     cate the error.

ERRORS
     The initgroups() function may fail and set errno for any of the errors specified for the library function setgroups(2).  It may also return:

     [ENOMEM]		The initgroups() function was unable to allocate temporary storage.

SEE ALSO
     setgroups(2), getgrouplist(3)

HISTORY
     The initgroups() function appeared in 4.2BSD.

BSD
								 October 26, 2014							       BSD