Nut/OS  4.10.3
API Reference
getenv.c
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00001 /*
00002  * Copyright 2008 by egnite Software GmbH
00003  *
00004  * Redistribution and use in source and binary forms, with or without
00005  * modification, are permitted provided that the following conditions
00006  * are met:
00007  *
00008  * 1. Redistributions of source code must retain the above copyright
00009  *    notice, this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright
00011  *    notice, this list of conditions and the following disclaimer in the
00012  *    documentation and/or other materials provided with the distribution.
00013  * 3. Neither the name of the copyright holders nor the names of
00014  *    contributors may be used to endorse or promote products derived
00015  *    from this software without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
00018  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
00019  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
00020  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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00023  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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00027  * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00028  * SUCH DAMAGE.
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00031  */
00032 
00033 #include <sys/environ.h>
00034 
00035 static char empty_envval[1] = {0};
00036 
00045 char *getenv(CONST char *name)
00046 {
00047     NUTENVIRONMENT *envp;
00048 
00049     if ((envp = findenv(name)) == NULL) {
00050         return NULL;
00051     }
00052     if (envp->env_value != NULL) {
00053         return envp->env_value;
00054     }
00055     return empty_envval;
00056 }
00057 
00068 char *nextenv(CONST char *name)
00069 {
00070     NUTENVIRONMENT *envp;
00071 
00072     if (name && *name) {
00073         if ((envp = findenv(name)) != NULL && envp->env_next != NULL) {
00074             return envp->env_next->env_name;
00075         }
00076     } 
00077     else if (nut_environ) {
00078         return nut_environ->env_name;
00079     }
00080     return NULL;
00081 }