group.c

/**
   @file      group.c
   @author    Mitch Richling <http://www.mitchr.me/>
   @Copyright Copyright 1996 by Mitch Richling.  All rights reserved.
   @brief     UNIX group queries@EOL
   @Keywords  UNIX group user gid
   @Std       ISOC POSIX UNIX98 BSD4.3 SYSV3

              This is an example program intended to illustrate how to
              query most UNIX versions for user group data.

   @Tested    
              - Solaris 2.8
              - MacOS X.2
              - Linux (RH 7.3)
*/

#include <sys/types.h>          /* UNIX types      POSIX */
#include <grp.h>                /* UNIX groups     POSIX */
#include <stdlib.h>             /* Standard Lib    ISOC  */
#include <unistd.h>             /* UNIX std stf    POSIX */
#include <stdio.h>              /* I/O lib         ISOC  */

int main(int argc, char *argv[]);

int main(int argc, char *argv[]) {
  struct group *grEnt;
  int j, i = 0;

  while(NULL != (grEnt = getgrent())) {
    i++;
    printf("Group #%05d: %s:%s:%ld:", i, grEnt->gr_name, grEnt->gr_passwd, (long)grEnt->gr_gid);
    /* Now we go through the member list.  This is an array of
       pointers to chars(strings).  The end is marked with a
       pointer to NULL. */
    for(j = 0; grEnt->gr_mem[j] != NULL; j++)
      printf("%s%s", grEnt->gr_mem[j], (grEnt->gr_mem[j + 1] != NULL ? "," : ""));
    printf("\n");
  } /* end while */

  return 0;
} /* end func main */