...
For example, when compiled with GCC 3.4.6 and run on a 32-bit Intel GNU/Linux machine, the following code,
| Code Block |
|---|
extern char **environ;
/* ... */
int main(int argc, const char *argv[], const char *envp[]) {
printf("environ: %p\n", environ);
printf("envp: %p\n", envp);
setenv("MY_NEW_VAR", "new_value", 1);
puts("--Added MY_NEW_VAR--");
printf("environ: %p\n", environ);
printf("envp: %p\n", envp);
}
|
...
This noncompliant code example accesses the envp pointer after calling setenv().:
| Code Block | ||||
|---|---|---|---|---|
| ||||
int main(int argc, const char *argv[], const char *envp[]) {
size_t i;
if (setenv("MY_NEW_VAR", "new_value", 1) != 0) {
/* Handle error */
}
if (envp != NULL) {
for (i = 0; envp[i] != NULL; i++) {
if (puts(envp[i]) == EOF) {
/* Handle error */
}
}
}
return 0;
}
|
...
Use environ in place of envp when defined.:
| Code Block | ||||
|---|---|---|---|---|
| ||||
extern char **environ;
/* ... */
int main(int argc, const char *argv[]) {
size_t i;
if (setenv("MY_NEW_VAR", "new_value", 1) != 0) {
/* Handle error */
}
if (environ != NULL) {
for (i = 0; environ[i] != NULL; i++) {
if (puts(environ[i]) == EOF) {
/* Handle error */
}
}
}
return 0;
}
|
...
This noncompliant code example accesses the envp pointer after calling _putenvs().:
| Code Block | ||||
|---|---|---|---|---|
| ||||
int main(int argc, const char *argv[], const char *envp[]) {
size_t i;
if (_putenv_s("MY_NEW_VAR", "new_value") != 0) {
/* Handle error */
}
if (envp != NULL) {
for (i = 0; envp[i] != NULL; i++) {
if (puts(envp[i]) == EOF) {
/* Handle error */
}
}
}
return 0;
}
|
...
Use _environ in place of envp when defined.:
| Code Block | ||||
|---|---|---|---|---|
| ||||
_CRTIMP extern char **_environ;
/* ... */
int main(int argc, const char *argv[]) {
size_t i;
if (_putenv_s("MY_NEW_VAR", "new_value") != 0) {
/* Handle error */
}
if (_environ != NULL) {
for (i = 0; _environ[i] != NULL; i++) {
if (puts(_environ[i]) == EOF) {
/* Handle error */
}
}
}
return 0;
}
|
...
| [ISO/IEC 9899:2011] | Section J.5.1, "Environment Arguments" |
| [MSDN] | getenv, _wgetenv_environ, _wenviron_putenv_s, _wputenv_s |
| [Open Group 2004] | setenv() |
...