proc_open
(PHP 4 >= 4.3.0)
proc_open -- Execute a command and open file pointers for
input/output
Description
resource proc_open ( string cmd, array descriptorspec, array
pipes)
proc_open() is similar to popen() but provides a much greater
degree of control over the program execution. cmd is the
command to be executed by the shell. descriptorspec is an
indexed array where the key represents the descriptor number
and the value represents how PHP will pass that descriptor
to the child process. pipes will be set to an indexed array
of file pointers that correspond to PHP's end of any pipes
that are created. The return value is a resource representing
the process; you should free it using proc_close() when
you are finished with it.
<?php
$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("file", "/tmp/error-output.txt",
"a") // stderr is a file to write to
);
$process = proc_open("php", $descriptorspec, $pipes);
if (is_resource($process)) {
// $pipes now looks like this:
// 0 => writeable handle connected to child stdin
// 1 => readable handle connected to child stdout
// Any error output will be appended to /tmp/error-output.txt
fwrite($pipes[0], "<?php echo \"Hello World!\";
?>");
fclose($pipes[0]);
while (!feof($pipes[1])) {
echo fgets($pipes[1], 1024);
}
fclose($pipes[1]);
// It is important that you close any pipes before calling
// proc_close in order to avoid a deadlock
$return_value = proc_close($process);
echo "command returned $return_value\n";
}
?>
The file descriptor numbers in descriptorspec are not limited
to 0, 1 and 2 - you may specify any valid file descriptor
number and it will be passed to the child process. This
allows your script to interoperate with other scripts that
run as "co-processes". In particular, this is
useful for passing passphrases to programs like PGP, GPG
and openssl in a more secure manner. It is also useful for
reading status information provided by those programs on
auxiliary file descriptors.
Note: Windows compatibility: Descriptors beyond 2 (stderr)
are made available to the child process as inheritable handles,
but since the Windows architecture does not associate file
descriptor numbers with low-level handles, the child process
does not (yet) have a means of accessing those handles.
Stdin, stdout and stderr work as expected.
Note: If you only need a uni-directional (one-way) process
pipe, use popen() instead, as it is much easier to use.
See also stream_select(), exec(), system(), passthru(),
popen(), escapeshellcmd(), and the backtick operator.
