1#define _GNU_SOURCE
 2#include <grp.h>
 3#include <stdio.h>
 4
 5int putgrent(const struct group *gr, FILE *f)
 6{
 7	int r;
 8	size_t i;
 9	flockfile(f);
10	if ((r = fprintf(f, "%s:%s:%u:", gr->gr_name, gr->gr_passwd, gr->gr_gid))<0) goto done;
11	if (gr->gr_mem) for (i=0; gr->gr_mem[i]; i++)
12		if ((r = fprintf(f, "%s%s", i?",":"", gr->gr_mem[i]))<0) goto done;
13	r = fputc('\n', f);
14done:
15	funlockfile(f);
16	return r<0 ? -1 : 0;
17}