PHP CLI doesn't use stderr to output errors

Question

I'm running the PHP CLI through a NSTask in MacOS, but this question is more about the CLI itself.

I'm listening to the stderr pipe, but nothing is output there no matter what file I try to run:

• If the file type is not a plain text, stdout sets to ?.
• If the file is a php script with errors, the error messages are still printed to stdout.

Is there a switch to the interpreter to handle errors through stderr? Do I have an option to detect errors other than parsing stdout?

Answer 1

The display_errors directive (can be set everywhere) takes optionally the parameter "stderr" for it to report errors to stderr instead of stdout or completely disabled error output. Quoting from the PHP manual entry:

Value "stderr" sends the errors to stderr instead of stdout. The value is available as of PHP 5.2.4.

Alternatively if you're using the commandline interface and you want to output the errors your own you can re-use the command-line nput/output streams:

fwrite(STDERR, 'error message');

Here STDERR is an already opened stream to stderr.

Alternatively if you want to do it just for this script and not in CLI you can open a filed handler to php://stderr and write the error messages there.

$fe = fopen('php://stderr', 'w');
fwrite($fe, 'error message');