__ENV_LOCK(3) NEWLIB __ENV_LOCK(3)NAME
2.16 `__env_lock', `__env_unlock'--lock environ variable
SYNOPSIS
#include <envlock.h>
void __env_lock (struct _reent *REENT);
void __env_unlock (struct _reent *REENT);
DESCRIPTION
The `setenv' family of routines call these functions when they need to
modify the environ variable. The version of these routines supplied in
the library use the lock API defined in sys/lock.h. If multiple
threads of execution can call `setenv', or if `setenv' can be called
reentrantly, then you need to define your own versions of these func‐
tions in order to safely lock the memory pool during a call. If you do
not, the memory pool may become corrupted.
A call to `setenv' may call `__env_lock' recursively; that is, the
sequence of calls may go `__env_lock', `__env_lock', `__env_unlock',
`__env_unlock'. Any implementation of these routines must be careful
to avoid causing a thread to wait for a lock that it already holds.
SEE ALSO__env_lock is part of the library. The full documentation for is main‐
tained as a Texinfo manual. If info and are properly installed at your
site, the command
info
will give you access to the complete manual.
NEWLIB April 2010 __ENV_LOCK(3)
