#include <stdio.h>#include <grp.h>#define	CL	':'#define	CM	','#define	NL	'\n'#define	MAXGRP	100static char GROUP[] = "/etc/group";static FILE *grf = NULL;static char line[BUFSIZ+1];static struct group group;static char *gr_mem[MAXGRP];setgrent(){	if( !grf )		grf = fopen( GROUP, "r" );	else		rewind( grf );}endgrent(){	if( grf ){		fclose( grf );		grf = NULL;	}}static char *grskip(p,c)register char *p;register c;{	while( *p && *p != c ) ++p;	if( *p ) *p++ = 0;	return( p );}struct group *getgrent(){	register char *p, **q;	if( !grf && !(grf = fopen( GROUP, "r" )) )		return(NULL);	if( !(p = fgets( line, BUFSIZ, grf )) )		return(NULL);	group.gr_name = p;	group.gr_passwd = p = grskip(p,CL);	group.gr_gid = atoi( p = grskip(p,CL) );	group.gr_mem = gr_mem;	p = grskip(p,CL);	grskip(p,NL);	q = gr_mem;	while( *p ){		*q++ = p;		p = grskip(p,CM);	}	*q = NULL;	return( &group );}