Selectively disable GCC warnings for only part of a translation unit?

Question

What's the closest GCC equivalent to this MSVC preprocessor code?

#pragma warning( push )                    // Save the current warning state.
#pragma warning( disable : 4723 )          // C4723: potential divide by 0
// Code which would generate warning 4723.
#pragma warning( pop )                     // Restore warnings to previous state.

We have code in commonly included headers which we do not want to generate a specific warning. However we want files which include those headers to continue to generate that warning (if the project has that warning enabled).

Answer 1

The closest thing is the GCC diagnostic pragma, #pragma GCC diagnostic [warning|error|ignored] "-Wwhatever". It isn't very close to what you want, and see the link for details and caveats.

Answer 2

I've done something similar. For third-party code, I didn't want to see any warnings at all. So, rather than specify -I/path/to/libfoo/include, I used -isystem /path/to/libfoo/include. This makes the compiler treat those header files as "system headers" for the purpose of warnings, and so long as you don't enable -Wsystem-headers, you're mostly safe. I've still seen a few warnings leak out of there, but it cuts down on most of the junk.

Note that this only helps you if you can isolate the offending code by include-directory. If it's just a subset of your own project, or intermixed with other code, you're out of luck.

Answer 3

This is possible in GCC since around June 2010 (whatever version that corresponds with).

Here's an example:

#pragma GCC diagnostic error "-Wuninitialized"
    foo(a);         /* error is given for this one */
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wuninitialized"
    foo(b);         /* no diagnostic for this one */
#pragma GCC diagnostic pop
    foo(c);         /* error is given for this one */
#pragma GCC diagnostic pop
    foo(d);         /* depends on command line options */