I have a WAMP 2.2 server running on a Windows 7 box and cannot get PHP error logging working at all.
The file is always blank even after I explicitly trigger USER_ERROR errors, or cause normal ERROR errors.
I'm including the error relevant sections of the php.ini
file - hopefully you can find something:
error_reporting = E_ALL
error_log = "c:/wamp32/logs/php_error.log" ;(UNCOMMENTED BY ME)
log_errors = On
display_errors = On