SETENVSection: Linux Programmer's Manual (3)
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NAMEsetenv - change or add an environment variable
#include <stdlib.h> int setenv(const char *name, const char *value, int overwrite); int unsetenv(const char *name);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
DESCRIPTIONThe setenv() function adds the variable name to the environment with the value value, if name does not already exist. If name does exist in the environment, then its value is changed to value if overwrite is non-zero; if overwrite is zero, then the value of name is not changed. This function makes copies of the strings pointed to by name and value (by contrast with putenv(3)).
RETURN VALUEThe setenv() function returns zero on success, or -1 if there was insufficient space in the environment.
- name contained an '=' character.
CONFORMING TO4.3BSD, POSIX.1-2001.
NOTESPOSIX.1-2001 does not require setenv() or unsetenv() to be reentrant.
BUGSPOSIX.1-2001 specifies that if name contains an '=' character, then setenv() should fail with the error EINVAL; however, versions of glibc before 2.3.4 allowed an '=' sign in name.
SEE ALSOclearenv(3), getenv(3), putenv(3), environ(7)
COLOPHONThis page is part of release 3.21 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.