1: #include <grp.h>
    2: #include <pwd.h>
    3: #include <sys/types.h>
    4: #include <unistd.h>
    5: #include <stdlib.h>
    6: #include <stdio.h>
    7: 
    8: int
    9: main (int argc, char *argv[])
   10: {
   11:   uid_t me;
   12:   struct passwd *my_passwd;
   13:   struct group *my_group = NULL;
   14:   char **members;
   15: 
   16:   me = getuid ();
   17:   my_passwd = getpwuid (me);
   18:   if (my_passwd == NULL)
   19:     printf ("Cannot find user entry for UID %d\n", me);
   20:   else
   21:     {
   22:       printf ("My login name is %s.\n", my_passwd->pw_name);
   23:       printf ("My uid is %d.\n", (int)(my_passwd->pw_uid));
   24:       printf ("My home directory is %s.\n", my_passwd->pw_dir);
   25:       printf ("My default shell is %s.\n", my_passwd->pw_shell);
   26: 
   27:       my_group = getgrgid (my_passwd->pw_gid);
   28:       if (my_group == NULL)
   29:         printf ("No data for group %d found\n", my_passwd->pw_gid);
   30:       else
   31:         {
   32:           printf ("My default group is %s (%d).\n",
   33:                   my_group->gr_name, (int)(my_passwd->pw_gid));
   34:           printf ("The members of this group are:\n");
   35:           for (members = my_group->gr_mem; *members != NULL; ++members)
   36:             printf ("  %s\n", *members);
   37:         }
   38:     }
   39: 
   40:   return my_passwd && my_group ? EXIT_SUCCESS : EXIT_FAILURE;
   41: }