I have checked php.ini and

log_errors = On
error_log = "c:/wamp/logs/php_error.log" `

(the dir contain access.log, apache_error.log, log.dir, mysql.log)

there is no entry for "error_reporting" but there is a comment (which I did not quite understand)

; Eval the expression with current error_reporting().  Set to true if you want
; error_reporting(0) around the eval().
; http://php.net/assert.quiet-eval
;assert.quiet_eval = 0

I would appreciate it if someone could help me.

Just set it at runtime:

error_reporting(E_ALL | E_STRICT);
ini_set('display_errors', 1);

more