osx man page for pwcache

PWCACHE(3)						   BSD Library Functions Manual 						PWCACHE(3)

NAME
     pwcache -- cache password and group entries

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <pwd.h>

     char *
     user_from_uid(uid_t uid, int nouser);

     #include <grp.h>

     char *
     group_from_gid(gid_t gid, int nogroup);

DESCRIPTION
     The user_from_uid() function returns the user name associated with the argument uid.  The user name is cached so that multiple calls with the
     same uid do not require additional calls to getpwuid(3).  If there is no user associated with the uid, a pointer is returned to a string rep-
     resentation of the uid, unless the argument nouser is non-zero, in which case a NULL pointer is returned.

     The group_from_gid() function returns the group name associated with the argument gid.  The group name is cached so that multiple calls with
     the same gid do not require additional calls to getgrgid(3).  If there is no group associated with the gid, a pointer is returned to a string
     representation of the gid, unless the argument nogroup is non-zero, in which case a NULL pointer is returned.

SEE ALSO
     getgrgid(3), getpwuid(3)

HISTORY
     The user_from_uid() and group_from_gid() functions first appeared in 4.4BSD.

BSD
								   June 9, 1993 							       BSD