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Bug #44908 stream_select on pipes returned by proc_open returns streams that are not ready
Submitted: 2008-05-04 08:06 UTC Modified: 2014-09-29 14:49 UTC
Avg. Score:4.4 ± 0.9
Reproduced:12 of 12 (100.0%)
Same Version:5 (41.7%)
Same OS:7 (58.3%)
From: mike at silverorange dot com Assigned:
Status: Wont fix Package: Streams related
PHP Version: 5.2CVS-2008-09-08 OS: *
Private report: No CVE-ID: None
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From: mike at silverorange dot com
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 [2008-05-04 08:06 UTC] mike at silverorange dot com
When using stream_select() on pipes returned by proc_open() in Windows, input streams that are not ready are returned in the modified $read array.

Reproduce code:

$pipes = array();
$proc = proc_open('c:/progra~1/gnu/gnupg/gpg.exe', array(
     0 => array('pipe', 'r'),
     1 => array('pipe', 'w'),
     2 => array('pipe', 'w')), $pipes, null, $_ENV);

if ($proc !== false) {
    $write  = array($pipes[0]);
    $read   = array($pipes[1], $pipes[2]);
    $except = null;

    $changed = stream_select($read, $write, $except, null);

    if ($changed) {



Expected result:
The read array will be empty and the write array will contain stdin.

Actual result:
The read array contains stdin and the write array contains stdout and stderr. The stdout and stderr streams have no data ready and fread() will block indefinitely.


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 [2008-05-04 08:08 UTC] mike at silverorange dot com

Actual result:
The _write_ array contains stdin and the _read_ array contains stdout and stderr. The stdout and stderr streams have no data ready and fread() will block indefinitely.
 [2008-05-04 21:50 UTC]
Please check the used PHP version. (phpinfo(); usually is the best way)
 [2008-05-04 23:31 UTC] mike at silverorange dot com

I'm using the MSI install of PHP 5.2.6 (cli) (built Apr 30 2008 16:19:00) on Windows XP Home with Service Pack 2.
 [2008-05-27 15:46 UTC] pciocan at gmail dot com
I encountered the same problem with stream_select but when using named pipes (created with posix_mkfifo and opened using fopen). Is there a workaround for this problem?

Thank you,
 [2008-05-27 15:51 UTC] ciocan at gmail dot com
Sorry i forgot to mention that for me it happens in Linux: CentOS 5, php 5.2.6 (and also tried on CentoOS 5, php 5.2.1)

Thank you,
 [2008-09-08 14:51 UTC]

I tried the posted development snapshot and the test still fails. The stream_select() call still returns stdout and stderr streams  in the read array and reading from either will block indefinitely (because they're not ready).

Please reopen this bug.
 [2008-11-25 03:57 UTC]
Please try using this CVS snapshot:
For Windows:

 [2008-12-03 01:00 UTC] php-bugs at lists dot php dot net
No feedback was provided for this bug for over a week, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".
 [2009-02-07 11:01 UTC] ondraster at gmail dot com
function loadModule ( $moduleName ) {
 $descriptorspec = array(
  0 => array("pipe", "r"),
  1 => array("pipe", "w"),
  2 => array("file", "errors.txt", "a")
 $module = proc_open ( 'I:\httpd\php\php.exe I:\httpd\php-irc-bot\module.' . $moduleName . '.php', $descriptorspec, $pipes, NULL, array ( 'RUNFIRST' => true ) );
 $this -> runningModules[$moduleName] = $module;
 echo "Registered new module: $moduleName\r\n";
 $this -> pipes[$moduleName] = $pipes;		

... few code ...

foreach ( $this -> pipes as $module => $pipes ) {				
 fwrite ( $pipes[0], $msg );					
 $forChange[] = $pipes[1];					
$r = NULL;
$e = NULL;
$sock_change = stream_select ( $forChange, $r, $e, 0, 20 );				
if ( $sock_change > 0 && $sock_change !== false ) {				
foreach ( $forChange as $key => $stream ) {			
 echo fread ( $stream, 4096 );	

PHP 5.2.2, 5.2.8, 5.3 (Windows Vista 64bit, x86 build, running from CLI) still not working. After 3/4 of year still not fixed. PHP6 says some warnings, never seen before ("Cannot cast a filtered stream on this system", complete errors:
 [2014-09-29 14:49 UTC]
-Status: No Feedback +Status: Wont fix
 [2014-09-29 14:49 UTC]
see bug #47918
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