(PHP 4 >= 4.3.0, PHP 5, PHP 7)
proc_close — Close a process opened by proc_open() and return the exit code of that process
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 its 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.
Returns the termination status of the process that was run. In case of an error then -1 is returned.
If PHP has been compiled with --enable-sigchild, the return value of this function is undefined.