How do you define the term 'failing function'?

In a presentation about Zend Server, the author lists the features of Zend Monitor. One of these features is called:

• Zend Monitor will watch your a开发者_JAVA百科pplication for failing functions

What does this mean, if you subtract error and exception monitoring? How can you detect a failing function, if not through and error or uncaught exception?

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Hope it's not too late to give an answer "from the makers" (I work on Zend Server), but the "Function Error" events (as well as "Database Error" events) are triggered when one of the watched functions (defined in the monitoring rule) returns boolean FALSE.

This follows a pattern which is common especially in the more "traditional" PHP APIs (e.g. mysql, curl, openssl etc.) where some function will simply return FALSE to indicate failure, and you then are required to call a "get_errors()" function to see what went wrong.

This is unlike "normal" PHP errors which are E_ERROR, E_WARNING etc. error types, which some other PHP functions will raise when something fails.

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Besides being "marketing speak" ...

"failing function" means:

• PHP errors raised during function execution
• slow functions

See at
http://files.zend.com/help/Zend-Server/monitor.htm

The Zend Monitor [...] watches for various events such as errors, failing functions, slow scripts, database errors, etc. When an event occurs, the Zend Monitor collects and reports all the relevant debugging information.

What is an Event?

Events are governed by rules created in Rule Management | Monitor. Rules define the nature of an event and the parameters for capturing event related information in an application.

And you can see the events of the Rule Management here (search "Rule Management" in the page) :
http://www.oracle.com/technetwork/articles/vaswani-zend-083732.html

And also here :
http://static.zend.com/topics/Zend-Server-Reference-Manual-v403-2.pdf