mes/lib/posix/getenv.c

53 lines
1.4 KiB
C

/*
* GNU Mes --- Maxwell Equations of Software
* Copyright © 2016,2017,2018,2019,2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
*
* This file is part of GNU Mes.
*
* GNU Mes is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or (at
* your option) any later version.
*
* GNU Mes is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Mes. If not, see <http://www.gnu.org/licenses/>.
*/
#include <mes/lib.h>
#include <string.h>
#include <stdlib.h>
// CONSTANT M2_PTR_SIZE 8
#define M2_PTR_SIZE 1
char *
getenv (char const *s)
{
/* eputs ("\ngetenv s="); eputs (s); eputs ("\n"); */
char **p = environ;
char *q;
int length = strlen (s);
while (p[0] != 0)
{
/* eputs ("getenv p[0]="); eputs (p[0]); eputs ("\n"); */
if (strncmp (s, p[0], length) == 0)
{
/* eputs ("found!\n"); */
q = p[0] + length;
if (q[0] == '=')
return q + 1;
}
/* else */
/* eputs ("not found!\n"); */
p = p + M2_PTR_SIZE;
}
return 0;
}