compiler/posixc/getenv.c

   1 /*
   2     Copyright © 1995-2014, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     C99 function getenv().
   6 */
   7
   8 #include <proto/exec.h>
   9 #include <proto/dos.h>
  10
  11 #include "__env.h"
  12
  13 /*****************************************************************************
  14
  15     NAME */
  16 #include <stdlib.h>
  17
  18         char *getenv (
  19
  20 /*  SYNOPSIS */
  21         const char *name)
  22
  23 /*  FUNCTION
  24         Get an environment variable.
  25
  26     INPUTS
  27         name - Name of the environment variable.
  28
  29     RESULT
  30         Pointer to the variable's value, or NULL on failure.
  31
  32     NOTES
  33         The returned contents of the environment variable is cached per
  34         PosixCBase and per variable name. So the returned value is valid
  35         and does not change until a next call to getenv with the same
  36         PosixCBase and the same name.
  37
  38     EXAMPLE
  39
  40     BUGS
  41
  42     SEE ALSO
  43
  44     INTERNALS
  45         Based on libnix getenv
  46
  47 ******************************************************************************/
  48 {
  49     __env_item *var = NULL;
  50     char  c;
  51
  52     /*
  53       This will always return 0 if the var exists and EOF if it doesn't,
  54       then we'll be able to retrieve the var length with IoErr()
  55     */
  56     if (!GetVar((char *)name, &c, 1, GVF_BINARY_VAR))
  57     {
  58         LONG len = IoErr();
  59
  60         var = __env_getvar(name, len+1); /* size == len + null-byte. */
  61
  62         if (var)
  63         {
  64             /* This should not fail, unless someone stole our variable */
  65             /* FIXME: maybe this function should be atomic? */
  66             GetVar((char *)name, var->value, len+1, GVF_BINARY_VAR);
  67         }
  68     }
  69
  70     return (var?var->value:NULL);
  71 } /* getenv */
  72