build warnings

Kelly O'Hair kellyohair at
Wed Dec 3 17:42:32 UTC 2014

On Dec 3, 2014, at 3:09 AM, Magnus Ihse Bursie <magnus.ihse.bursie at> wrote:

> On 2014-12-02 22:59, Jonathan Gibbons wrote:
>> Build folk,
>> The build has always generated warnings (sigh!) but right now, the warnings look scarier than usual.
>> In particular, when the build terminates, I get a couple of screenfuls of messages like this:
>> /w/jjg/work/jfm2.0/dev.8059977.sjfm/jdk/src/java.desktop/unix/native/libsplashscreen/splashscreen_sys.c: In function ‘SplashScreenThread’:
>> /w/jjg/work/jfm2.0/dev.8059977.sjfm/jdk/src/java.desktop/unix/native/libsplashscreen/splashscreen_sys.c:742:9: warning: ignoring return value of ‘pipe’, declared with attribute warn_unused_result [-Wunused-result]
>>     pipe(splash->controlpipe);
>>         ^
>> /w/jjg/work/jfm2.0/dev.8059977.sjfm/jdk/src/java.desktop/share/native/libsplashscreen/splashscreen_gfx_impl.c: In function ‘initFormat’:
>> /w/jjg/work/jfm2.0/dev.8059977.sjfm/jdk/src/java.desktop/share/native/libsplashscreen/splashscreen_gfx_impl.c:305:34: warning: ‘numBits’ may be used uninitialized in this function [-Wmaybe-uninitialized]
>>         format->shift[i] = shift + numBits - i * 8 - 8;
>>                                  ^
>> What would it take to have some sort of campaign to reduce build warnings like these?  We've made good progress on lint and doclint warnings for Java code and doc comments; what does it take to start on native code warnings?
> Actually, I've already started on such a campain. ;-)
> I believe the way to go is:
> 1) disable all (or more or less all) of the current flood of warnings
> 2) open bugs for all disabled warnings on the corresponding components, indicating that the owner of the component should:
> a) fix the issue with the source code and re-enable the warning, or
> b) come up with a good reason why the warning is bad/broken and should be left disabled for that component.
> I have started on 1). I have a local forest which disables most of the warnings for linux builds. I'm about to move on to the other platforms as well, but other work came between.
> /Magnus

Speaking from a bit of experience, if you disable the warnings, odds are good that they will never get fixed because being disabled will be considered by some as "we have no warnings" and they will work on other things, like adding more code with more invisible disabled warnings. Granted some of the C/C++ compiler warnings are very dubious and of little value, but many are not. Disabling the less valuable warnings makes sense, but I would caution on disabling all warnings. Just my 2 cents...


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