(PHP 4 = 4.3.0)
proc_close() is similar to
pclose() except that it only works on processes
opened by proc_open().
proc_close() waits for the process to terminate, and
returns it's exit code. If you have open pipes to that
process, you should fclose() them prior to calling this
function in order to avoid a deadlock - the child process may
not be able to exit while the pipes are open.