[asterisk-dev] [Code Review] 4554: clang compiler warning: -Wunused-value

[Diederik de Groot]

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This is an automatically generated e-mail. To reply, visit:
https://reviewboard.asterisk.org/r/4554/
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(Updated April 4, 2015, 1:15 a.m.)


Review request for Asterisk Developers.


Bugs: ASTERISK-24917
    https://issues.asterisk.org/jira/browse/ASTERISK-24917


Repository: Asterisk


Description
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clang's static analyzer will throw quite a number warnings / errors during compilation, some of which can be very helpfull in finding corner-case bugs. 

clang compiler warning:-Wunused-value

Changes:
apps/app_agent_pool.c
multiple occasions where return value from ast_channel_ref and ast_channel_unref is not checked not used.
return value from AST_LIST_REMOVE should be checked.
Possible issues with leaked logged reference (added remark)

channels/chan_iax2.c
return values from ast_callid_ref and ast_callid_unref can/should be used to update the pointer
return value from AST_SCHED_DEL should be used to update the scheduled variable
return value from AST_LIST_REMOVE should be checked.

channels/iax2/parser.c
return value from AST_LIST_REMOVE should be checked.

include/asterisk/stringfields.h
Quick fix to send the returned value from ast_string_field_ptr_set into the void.

Work in Progress:
There are too many sources issues with "-Wunused-value" for one person to create all the fixes. If we want to actually use this warning we will need a couple of extra hands-on.

Should we suppress "-Wunused-value" ? :
I think some of the issues pointed out by clang could be very helpfull, for example the "unref/ref/AST_LIST_REMOVE" changes that where needed in chan_iax2.c and apps/app_agent_pool.c. Some others a less interesting, for example the SCHED_DEL fixes.


Diffs (updated)
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  /branches/13/include/asterisk/stringfields.h 433444 
  /branches/13/channels/iax2/parser.c 433444 
  /branches/13/channels/chan_iax2.c 433444 
  /branches/13/apps/app_agent_pool.c 433444 

Diff: https://reviewboard.asterisk.org/r/4554/diff/


Testing
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Just to make it clear, this was just a sample / proposal to work through large set of -Wunused-value warnings return. Some of them could be interesting, others might not be be. 

Mostly looking for a discussion about which path to follow, and see if we can divvy up the work a little.

Compiles / Untested / Pretty certain it contains issue because of different way of dealing with return value from ..._unref.


File Attachments
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ASTCFLAGS="-Wno-error=unused-value" make &| grep "[-W" -B1 -A2
  https://reviewboard.asterisk.org/media/uploaded/files/2015/03/28/83f2f382-9ef2-41cf-8e7a-c188c014c17e__make.report


Thanks,

Diederik de Groot

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