Kevin Fleming: So, you want to be an Asterisk Developer?

Kevin Fleming discussed the task of becoming an Asterisk Developer:

Discussed Libraries Required
Debugging
Easier to debug post-mortem
Threading models differ by platform
use make dont-optimize
check makefiles for debugging defines
ensure that 'debug' is listed for the console
always use the -g parameter
use 'thread apply all bt full' in gdb
use 'ast_grab_core' (helpful for solving deadlocks)

Patches

always run 'make update'
use 'cvs diff -u' (or add 'diff -u' to your .cvsrc file)
read the patch before submitting
Watch for new/removed files
keeping out of tree patches up to date can be hard work

Licencing

Asterisk, Zaptel and LibPRI are dual licenced (GPL and to Digium for commercial distribution)
Contributions must be disclaimed
Code can not violate patents etc
If you make changes you are not required to distribute them
You are not required to submit changes to Asterisk, although it is recommended
If your code is committed it will be maintained by Asterisk crew
The code you have is GPL forever
The word Asterisk is trademarked
Always disclaim your code
You do not lose copyright on the code when you disclaim

Misc

Prototypes are in module.h
Use Use Count Tracking - needed for dynamically loadable modules
usecount function is called by the loader
Use the macros to implement basic usecount management
Module has to tell Asterisk what they can do
Application Modules are supposed to work on a channel that they are provided on
Applications MUST keep use counts
Channel modules are probably the most complicated part of Asterisk (allow connection to the outside world). Contains usecount again. Provide approx 25 methods that channels may provide
Codec Modules are the means of converting from one format of audio to another. Quite simple. Many codecs keep internal state from one frame to another.
Format Modules - provide means to read and write audio formats in all of the formats Asterisk supports
Function Modules - look like variables. Currently only in CVS HEAD. They provide dialplan functions. Most of these are built into pbx_functions.so
CDR Modules - these provide CDR backends to post CDRs into storage systems (DB/txt etc)

End of first part. He's a good speaker.

:)

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