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.
$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 auxillary file
descriptors.
注意 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.
注意 This function was introduced in PHP 4.3.0.
注意 If you only need a uni-directional (one-way) process pipe, use popen() instead, as it is much easier to use.
See also
exec()
,
system()
,
passthru()
,
popen()
,
escapeshellcmd()
, and the
backtick
operator
.