Debugging an NT Service

Debugging an NT service is hard for the following reasons:

• a service runs 'behind the scenes' and there is nothing visible for a user to see;
• the service is under the control of the machine -- the NT Service Manager looks after all services -- and not under direct user control.

When testing your NtService class, run it in the Carapace interpreter. Finally, when it looks to be working as desired, run it as an installed NT service.

Carapace services write to NT's Event Log at the following stages:

• installation
• startup
• shutdown
• de-installation

If the service fails to start, the Event Log is the first place to look. If you have any catastrophic errors (eg. you registered the service using the wrong Carapace script name) then you will see an error record in the event log.

Finally, a Carapace NT service requires you to have a log in your NtService object. This is so that your service can write to a log file and record what it is doing. Of course, a log is no use if nothing relevant is written to it!

When run as an NT service, the following script function is available to a Carapace script:

logEvent

Write the supplied message to the system's application Event Log at the supplied severity level. The severity level can be one of the following:

• info
• warn
• error

Arguments:

Return type: returns the empty List ()