proc_close

From various Internet posts and recent experience, I have observed that you cannot rely on proc_close returning the accurate return code of the child process. The return code also depends on wether or not you read from the stdout/stderr pipes, as my example shows. I work around this by writing the exit code to an additional file descriptor.<?$descriptorspec = array(       0 => array('pipe', 'r'),  // stdin is a pipe that the child will read from       1 => array('pipe', 'w'),  // stdout is a pipe that the child will write to       2 => array('pipe', 'w'), // stderr is a pipe that the child will write to    );    $proc = @proc_open("/bin/ls -l /etc/passwd", $descriptorspec, $pipes);    fclose($pipes[0]);    $output = array();    while (!feof($pipes[1])) array_push($output, rtrim(fgets($pipes[1],1024),"\n"));    fclose($pipes[1]);    while (!feof($pipes[2])) array_push($output, rtrim(fgets($pipes[2],1024),"\n"));    fclose($pipes[2]);    $exit=proc_close($proc);    print_r($output);    echo "exitcode $exit\n\n";$descriptorspec = array(       0 => array('pipe', 'r'),  // stdin is a pipe that the child will read from       1 => array('pipe', 'w'),  // stdout is a pipe that the child will write to       2 => array('pipe', 'w'), // stderr is a pipe that the child will write to    );    $proc = @proc_open("/bin/ls -l /etc/passwd", $descriptorspec, $pipes);    fclose($pipes[0]);    fclose($pipes[1]);    fclose($pipes[2]);    $exit=proc_close($proc);    echo "exitcode $exit\n\n";$descriptorspec = array(       0 => array('pipe', 'r'),  // stdin is a pipe that the child will read from       1 => array('pipe', 'w'),  // stdout is a pipe that the child will write to       2 => array('pipe', 'w'), // stderr is a pipe that the child will write to       3 => array('pipe', 'w'), // stderr is a pipe that the child will write to    );    $proc = @proc_open("/bin/ls -l /etc/passwd;echo $? >&3", $descriptorspec, $pipes);    fclose($pipes[0]);    $output = array();    //comment next line to get correct exicode    while (!feof($pipes[1])) array_push($output, rtrim(fgets($pipes[1],1024),"\n"));    fclose($pipes[1]);    while (!feof($pipes[2])) array_push($output, rtrim(fgets($pipes[2],1024),"\n"));    fclose($pipes[2]);    if (!feof($pipes[3])) $output['exitcode']=rtrim(fgets($pipes[3],5),"\n");    fclose($pipes[3]);    proc_close($proc);    print_r($output);?>Outputs on my system:Array(    [0] => -rw-r--r--  1 root root 1460 2005-09-02 09:52 /etc/passwd    [1] =>    [2] =>)exitcode -1exitcode 1Array(    [0] => -rw-r--r--  1 root root 1460 2005-09-02 09:52 /etc/passwd    [1] =>    [2] =>    [exitcode] => 0)

Regarding: "Returns the termination status of the process that was run. In case of an error then -1 is returned."This is, at best, misleading. It returns:* -1 on error,* WEXITSTATUS(status) if WIFEXITED(status) is true, or * status if WIFEXITED(status) is false,where status is the status parameter of waitpid().This makes it impossible to differentiate between a relatively normal exit or a termination by signal, and reduces the value of the proc_close return code to a binary one (ok / something broke).This can be seen in proc_open_rsrc_dtor() in ext/standard/proc_open.c (PHP 5.4.44, 5.6.12).

It seems that if you configured --enable-sigchild when you compiled PHP (which from my reading is required for you to use Oracle stuff), then return codes from proc_close() cannot be trusted.Using proc_open's Example 1998's code on versions I have of PHP4 (4.4.7) and PHP5 (5.2.4), the return code is always "-1".  This is also the only return code I can cause by running other shell commands whether they succeed or fail.I don't see this caveat mentioned anywhere except on this old bug report -- http://bugs.php.net/bug.php?id=29123

Under PHP/4.3.3RC2, in case of two processes these function may hangs. Work around is not use proc_close, or put it after all fcloses done. For example, this code hangs.$ph1 = proc_open("cat", array(0=>array("pipe","r"),1=>array("pipe","w")), $pipes1);$ph2 = proc_open("cat", array(0=>array("pipe","r"),1=>array("pipe","w")), $pipes2);fclose($pipes1[0]); fclose($pipes1[1]); proc_close($ph1);fclose($pipes2[0]); fclose($pipes2[1]); proc_close($ph2);This code worked for me:$ph1 = proc_open("cat", array(0=>array("pipe","r"),1=>array("pipe","w")), $pipes1);$ph2 = proc_open("cat", array(0=>array("pipe","r"),1=>array("pipe","w")), $pipes2);fclose($pipes1[0]); fclose($pipes1[1]); fclose($pipes2[0]); fclose($pipes2[1]); proc_close($ph1); proc_close($ph2);

Consider the following pseudo code:$SOME_PROCESS = proc_open(/* something here */);...$status = proc_get_status($SOME_PROCESS);...$exitCode = proc_close($SOME_PROCESS);If the external program has exited on its own before the call to proc_get_status, then $exitCode == -1So consider using:$actualExitCode = ($status["running"] ? $exitCode : $status["exitcode"] );