The putenv() function shall use the string argument to set
environment variable values. The string argument should point to a
string of the form " name= value ". The
putenv() function shall make 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 shall become
part of the environment, so altering the string shall change the environment.
The space used by string is no longer used once a new string which
defines name is passed to putenv().
The putenv() function need not be reentrant. A function that is not
required to be reentrant is not required to be thread-safe.
The putenv() function manipulates the environment pointed to by
environ, and can be used in conjunction with getenv().
See exec() , for restrictions on changing the environment in
This routine may use malloc() to enlarge the environment.
A potential error is to call putenv() with an automatic variable as the
argument, then return from the calling function while string is still
part of the environment.
The setenv() function is preferred over this function.
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html