putenv(S)
putenv --
change or add value to environment
Synopsis
#include <stdlib.h>
int putenv (char string);
Description
string
points to a string of the form
``name=value.''
putenv
makes the value of the environment variable
name
equal to
value
by altering an existing variable or creating a new one.
In either case, the string pointed to by
string
becomes part of the
environment, so altering the string will change the environment.
string
should not be a local (stack allocated) variable, since returning
from the current function and calling a new one will change the
environment.
If
name
is later redefined by another
putenv,
string
is no longer used.
It may be altered or reused without affecting the environment.
Return values
putenv
returns non-zero
if it was unable to obtain enough space
via
malloc
for an expanded environment,
otherwise zero.
References
environ(M),
exec(S),
getenv(S),
malloc(S)
Notices
putenv
manipulates the environment pointed to by
``environ'',
and can be used in conjunction with
getenv.
However,
envp
(the third argument to
main)
is not changed.
This routine uses
malloc(S)
to enlarge the environment.
After
putenv
is called, environment variables are not in
alphabetical order.
A potential error is to call the function putenv
with a pointer to an automatic variable as the argument and to
then exit the calling function while string is still part of the
environment.
© 2005 The SCO Group, Inc. All rights reserved.
SCO OpenServer Release 6.0.0 - 01 June 2005