Composer.phar does not want to run shell_exec from a PHP script. What for?

Question

Trying to execute it with all possible options such as -d and full path, etc. No mistakes. When you start other commands, everything is in order; when you start the composer from CMD, everything is in order. Tried exec, system, shell_exec, etc. What could it be?

echo system ('php composer.phar install');

Answer 1

Try also outputting a stream of errors:

system('php composer.phar install 2>&1'); 

This may give you more hint of what is going wrong.