proc_open
Execute a command and open file pointers for input/output
Descriptionresourceproc_openstringcmdarraydescriptorspecarraypipesproc_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.
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], "");
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.
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.
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.