1  /* Test of environ variable.
       2     Copyright (C) 2008-2023 Free Software Foundation, Inc.
       3  
       4     This program is free software: you can redistribute it and/or modify
       5     it under the terms of the GNU General Public License as published by
       6     the Free Software Foundation, either version 3 of the License, or
       7     (at your option) any later version.
       8  
       9     This program is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      12     GNU General Public License for more details.
      13  
      14     You should have received a copy of the GNU General Public License
      15     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      16  
      17  /* Written by Bruno Haible <bruno@clisp.org>, 2008.  */
      18  
      19  #include <config.h>
      20  
      21  #include <unistd.h>
      22  
      23  #include <string.h>
      24  
      25  int
      26  main ()
      27  {
      28    /* The environment variables that are set even in the weirdest situations
      29       are HOME and PATH.
      30       POSIX says that HOME is initialized by the system, and that PATH may be
      31       unset.  But in practice it's more frequent to see HOME unset and PATH
      32       set.  So we test the presence of PATH.  */
      33    char **remaining_variables = environ;
      34    char *string;
      35  
      36    for (; (string = *remaining_variables) != NULL; remaining_variables++)
      37      {
      38        if (strncmp (string, "PATH=", 5) == 0)
      39          /* Found the PATH environment variable.  */
      40          return 0;
      41      }
      42    /* Failed to find the PATH environment variable.  */
      43    return 1;
      44  }