I'm working on a project that will read compiler error messages of a particular variety and do useful things with them. The sample codebase I'm testing this on (a random open-source application), and hence rebuilding frequently, contains a few bits that generate warnings, which are of no interest to me.
How do I disable all warnings from GCC, so I can just see error messages if there are any?
-w is the GCC-wide option to disable warning messages.
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When I build Boost (1.69) with b2 on my system (Devuan ASCII), I get several warning messages about "non-free usage":
warning: non-free usage requirements <runtime-link>shared ignored
warning: in main-target build_options at libs/locale/build/Jamfile.v2:414
warning: non-free usage requirements <runtime-link>shared ignored
warning: in main-target build_flags at libs/locale/build/Jamfile.v2:415
My questions:
What do these messages mean?
Why am I getting them?
Can I / Should I do something to avoid them?
What do these messages mean?
It means that there's a build feature that normally propagates "downwards" is being specified to propagate "upwards". In this case as a "usage-requirement". This can be a problem as it can cause your target to change how it's built from using a different library.
Why am I getting them?
They come from usage-requirements in the Boost.Locale library here. AFAICT it's a bug in the library's build file.
Can I / Should I do something to avoid them?
I think you (a) should report it as a bug to the authors and (b) ignore it for now since as far as I can tell those targets do not affect the overall build of the library itself nor of other Boost libraries.
Does gcc define a macro of some sort when the flag -fprofile-generate is specified? Basically, I want to disable multithreading when I'm profiling--it seems to have a way of corrupting the .gcda files.
This unanswered question is quite old, but I was having similar issues, so I hope this can be useful to someone.
You should try enabling the -fprofile-correction GCC compiler flag when using the profile information generated by a multi-threaded application. According to the GCC documentation relative to this flag:
Profiles collected using an instrumented binary for multi-threaded programs may be inconsistent due to missed counter updates. When this option is specified, GCC uses heuristics to correct or smooth out such inconsistencies. By default, GCC emits an error message when an inconsistent profile is detected.
It will get rid of the errors indicating that the .gcda files are corrupted by correcting inconsistent profile values due to multi-threading.
I find it difficult sometimes to locate errors/warnings in large projects upon make-ing (gnu). How do I segregate the errors/warnings from the usual compilation messages when the error does not stop the build process from going any further? A wrapper shell script could pick and display whatever I want, but before fleshing out one I thought of asking about the alternatives.
Thanks.
In theory, make -s will suppress the "routine" output of the build process, leaving you with only the errors and warnings. Also in theory, make will stop as soon as it encounters an error.
If either of those is not true for the project(s) you're working with, that's probably due to poorly written makefiles. So fixing the makefiles is one alternative.
To help make sense of verbose builds, some simple highlighting as provided by colorgcc can go a long way. IDEs like eclipse or even emacs can also helpfully pick out the error messages in the build output.
Also, it might be helpful to note that warning and error messages are usually written to stderr, while everything else goes to stdout. So it might be useful to simply discard stdout like so: make >/dev/null.
I compile my Xcode projects with very high warnings settings. Sometimes, I have to use third-party frameworks that are distributed as source (rather than as a framework). These frameworks often throw a lot of warnings.
Is there a way to turn off warnings for these folders? I want the stricter level for my own code, but don't care if third-party code violates my warnings level.
Basically, I don't want to see 67 warnings every time I build.
You're looking for this:
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
Flags can be found here: http://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Warning-Options.html
Just replace the -W... with whatever you want to ignore.
I'd like my Xcode project to go through a Build And Analyze step without generating any errors, warnings, or static analysis messages. A problem with this is that my project includes libraries that generate (possibly innocuous) warnings and static analysis messages.
I can't find a way to disable specific Clang warnings so that "my" code builds with zero issues. Is this possible?
I wasn't able to find any way to do this, and filed a bug against Clang. The team seems to want to add this functionality, but it's not there yet.
The bug is: http://llvm.org/bugs/show_bug.cgi?id=7296
Also, one can use a __clang_analyzer__ macro to ifdef out any code that one doesn't want Clang to process.
The Build and Analyze step is clang - thats the "analyze" part. It wouldn't make sense to analyze your code and not have clang tell you about issues it find. That's like going to a car wash and telling them not to touch the car.
From talking to the guy that wrote clang at WWDC, it is extremely unlikely that anything it identifies as an issue is actually not. If you think you have some examples of code that works fine but clang complains, please file a bugreport with example code so Apple can fix that.
You can disable some compiler warnings through the use of flags, but not all of them are an option.