[asterisk-users] How to write a function with a return value in Asterisk

[Anthony Francis]

Mike wrote:
> Thanks for all the replies, after some thinking AGI seems like the way 
> to go (writing a function in C would certainly work, but I want to 
> avoid anything that makes upgrading to newer version of Asterisk a 
> potential pain.  Let's say using C is plan B).
>  
> So, I wrote (well, plagarized directly from the Web) a simple Perl 
> program that prints "Hello World".  I call it using this:
>  
> exten => 12345,1,AGI(agi-helloworld.agi)
>  
> Seems to work (I'm not expecting anything, really, just no Asterisk 
> error).
>  
> When I try to use it as part Noop like this:
> exten => 12345,1,Noop(${AGI(agi-helloworld.agi)})
>  
> In the hope of getting to see Noop(Hello World) in my CLI, I get the 
> following Asterisk error:
>  
> Aug  8 13:40:48 ERROR[5771]: pbx.c:1402 ast_func_read: Function AGI 
> not registered
>  
> AGI certainly seems registered as it worked in the first case.  Again, 
> something obvious I missed?
>  
> Thank you,
>  
> Mike
>  
>  
>
> ------------------------------------------------------------------------
> *From:* asterisk-users-bounces at lists.digium.com 
> [mailto:asterisk-users-bounces at lists.digium.com] *On Behalf Of 
> *Anthony Francis
> *Sent:* Wednesday, August 08, 2007 12:39
> *To:* Asterisk Users Mailing List - Non-Commercial Discussion
> *Subject:* Re: [asterisk-users] How to write a function with a return 
> value in Asterisk
>
> You are looking for the AGI: http://www.voip-info.org/wiki-Asterisk+AGI
>
> Anthony
>
> James FitzGibbon wrote:
>> On 8/8/07, *Mike* <list at virtutel.ca <mailto:list at virtutel.ca>> wrote:
>>
>>     I'd be most thankful for some link to a page that shows how to
>>     write such a
>>     function in Asterisk.
>>
>>
>> There is a test application in the source tree (not built by default 
>> I believe), but it doesn't look like anyone has made an equivalent 
>> sample function.
>>
>> However, many of the functions in 1.4 are pretty simple, and would be 
>> a good jumping off point.  Take func_sha1.c for example: 83 lines in 
>> the file, 4 functions and one macro.  You could copy that and do the 
>> proper renaming to make MY_FUNKY_NEW_FUNC that does exactly what 
>> func_sha1 does (or alternatively, nothing by getting rid of the bulk 
>> of the sha1() function therein.
>>
>> How big it gets as you add whatever magic that function should 
>> perform is up to you of course.
>>
>> -- 
>> j.
>> ------------------------------------------------------------------------
>>
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Yeah to assign a return variable you need to consult the AGI 
documentation for the perl variant of setvar. In other words, you call 
the AGI the first way, have the agi set the var, then you can ref the 
var in later steps.

Anthony