Originální popis anglicky:
setenv - change or add an environment variable
Návod, kniha: Linux Programmer's Manual
#include <stdlib.h>
int setenv(const char *name, const char *value, int overwrite);
int unsetenv(const char *name);
The
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.
The
unsetenv() function deletes the variable
name from the
environment.
The
setenv() function returns zero on success, or -1 if there was
insufficient space in the environment. The
unsetenv() function returns
zero on success, or -1 on error, with
errno set to indicate the cause
of the error.
- EINVAL
- name contained an '=' character.
BSD 4.3
Prior to glibc 2.2.2,
unsetenv() was prototyped as returning
void;
more recent glibc versions follow the SUSv3-compliant prototype shown in the
SYNOPSIS.
SUSv3 specifies that if
name contains an '=' character, then
setenv() should fail with the error
EINVAL; however, glibc
currently (v2.3.3) allows an '=' sign in
name. Portable applications
should avoid this!
clearenv(3),
getenv(3),
putenv(3),
environ(5)
