Re: [sr-dev] [kamailio/kamailio] not properly compassion (#2701)

That sdp function returns 4, 6 or -1.

The true for comparing with 1 happens because of how return code for functions is evaluated: negative values are evaluated to false and positive values are evaluated to true -- that is something specific for kamailio config interpreter, existing pretty much from the day 0 of the ser project.

It is documented in core cookbook in the section for return and in the FAQ:

* https://www.kamailio.org/wiki/tutorials/faq/main#how_is_the_function_return_...

Where I just added an explicit example for this case. Try the variant with getting the return value via $rc and if does not work reopen. Also the default config file has a similar approach for lookup location evaluation.