putenv - Sets an environment variable
const char *string );
The following syntax is for XSH5.0-compliant interfaces:
char *string );
Standard C Library (libc)
Interfaces documented on this reference page conform to
industry standards as follows:
putenv(): XSH4.0, XSH4.2, XSH5.0, POSIX.1
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
Points to a name=value string.
The putenv() function sets the value of an environment
variable by altering an existing variable or by creating a
new one. The new environment variable remains in effect
even after the program setting it is exited.
The string parameter points to a string of the form
"name=value", where name is the environment variable and
value is the new value for it.
The putenv() function manipulates the environ external
variable, and it can be used in conjunction with the
getenv() function. However, the third parameter to the
main function (the environment pointer) is not changed.
The putenv() function uses the malloc() function to
enlarge the environment.
A potential error is to call putenv() with an automatic
variable as the argument and then exit the calling function
while string is still part of the environment.
Upon successful completion, a value of 0 (zero) is
returned. If the malloc() function is unable to obtain
sufficient space to expand the environment, the putenv()
function returns a nonzero value.
Functions: clearenv(3), exec(2), getenv(3), malloc(3)
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