(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
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. Open pipes to that process are closed when this function is called, 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.
Note:
If PHP has been compiled with --enable-sigchild, the return value of this function is undefined.