need to send alert mail

hi,

i need to monitor a cron job that runs every 5 mins. if this cron job does not process the request for more than 6 hrs, an alert mail should be sent.
how do i achieve this??

Depending on the OS type, the logs for cron execution may vary, look at /var/ folder to find cron's logs, then take the time stamps.
Example on Fedora 8 :
cat /var/log/cron