logname.c

   1 /* `logname.c` - return the user's login name
   2    Copyright (c) 2022, Alan Potteiger
   3    See `LICENSE` for copyright and license details */
   4
   5 #define _POSIX_C_SOURCE 200809L
   6
   7 #include <stdio.h>
   8 #include <unistd.h>
   9
  10 static const char *usage = {
  11         "usage: logname\n"
  12 };
  13
  14 int
  15 main(int argc, char *argv[])
  16 {
  17         char *name;
  18
  19         name = getlogin();
  20         if (name == NULL) {
  21                 fputs("logname: login name not set\n", stderr);
  22                 return 1;
  23         }
  24
  25         puts(name);
  26         return 0;
  27 }
  28