Retrieve the error number set by the last posix function that failed. The system error message associated with the errno may be checked with posix_strerror().
Returns the errno (error number) set by the last posix function that failed. If no errors exist, 0 is returned.
This example attempt to kill a bogus process id, which will set the last error. We will then print out the last errno.
echo 'Your error returned was '.posix_get_last_error(); //Your error was ___