getenv.c (1399B)
1 /* 2 * GNU Mes --- Maxwell Equations of Software 3 * Copyright © 2016,2017,2018,2019,2020,2022 Jan (janneke) Nieuwenhuizen <janneke@gnu.org> 4 * 5 * This file is part of GNU Mes. 6 * 7 * GNU Mes is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 3 of the License, or (at 10 * your option) any later version. 11 * 12 * GNU Mes is distributed in the hope that it will be useful, but 13 * WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with GNU Mes. If not, see <http://www.gnu.org/licenses/>. 19 */ 20 21 #include <mes/lib.h> 22 #include <string.h> 23 #include <stdlib.h> 24 25 char * 26 getenv (char const *s) 27 { 28 /* eputs ("\ngetenv s="); eputs (s); eputs ("\n"); */ 29 char **p = environ; 30 char *q; 31 int length = strlen (s); 32 33 while (p[0] != 0) 34 { 35 /* eputs ("getenv p[0]="); eputs (p[0]); eputs ("\n"); */ 36 if (strncmp (s, p[0], length) == 0) 37 { 38 /* eputs ("found!\n"); */ 39 q = p[0] + length; 40 if (q[0] == '=') 41 return q + 1; 42 } 43 /* else */ 44 /* eputs ("not found!\n"); */ 45 p = p + M2_PTR_SIZE; 46 } 47 48 return 0; 49 }