Asterisk: The Future of Telephony, 2nd Edition

Name

NoOp() — Does nothing

Synopsis

NoOp(text)

Does nothing—this application is simply a placeholder. This application is often used as a debugging tool. Whenever Asterisk’s core verbosity level is set to 3 or above, Asterisk evaluates and prints each line of the dialplan before executing it. This means that any arguments passed to the NoOp() application (in the text parameter) are printed to the console. By watching the console output, a skilled Asterisk administrator can use this output to debug problems in the dialplan.

exten => 123,1,NoOp(CallerID is ${CALLERID})

Tip

You don’t have to place quotes around the text. If quotes are placed within the brackets, they will show up on the console.

When to use NoOp() and Verbose()

The difference between Verbose() and NoOp() is subtle. Here are some suggestions as to how you can discern when to use each. The Verbose() application is handy when you want to output something to the console. Using the set verbose command (followed by the level of verbosity you desire—0 to 4), you can set the output to a level that will not show you all of the activity on the system, but rather only those things that are equal to or less than that the current level. (Actually, you can set the verbosity to whatever you want. The set verbose 999 will work just fine, but we have not been able to find anything that outputs at a level higher than 4, so anything from 4 to infinity will be effectively the same for the time being.) This means that you can display all kinds ...