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Comment by CamperBob2 | Hacker News Reader

I use -W4 and -WX with MSVC to enable the highest warning level and flag all warnings as errors. Then I disable a couple of the more pointless warnings (unreferenced formal parameter, unreferenced local function, unreachable code...) that would otherwise keep me from being able to use -W4 without jumping through arbitrary hoops.

The problem with GCC, at least at the time I was using it several years ago, is that there seemed to be no way to disable individual warnings. Is that still true (or was it ever?)

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GCC has pretty much always had `-Wno-YOUR_SPECIFIC_ERROR`.

By that, I mean it was present in a random version from 1993 (2.4.5). But it wasn't there in 1987 (1.35, the oldest version that can be easily downloaded), so it didn't literally always have it.

Edit: I wasn't satisfied not knowing; so I dug through some more versions. The -Wno- flags were introduced in GCC 2.0 (1992). (Though only tracked down 1.41, not 1.42, the last of the 1.X line).

-Wno-specific-warning (I think it's always had this, or at least for a very long time).

And:

  #pragma GCC diagnostic push
  #pragma GCC diagnostic warning "-Wspecific-warning"
  #pragma GCC diagnostic ignored "-Wspecific-warning"
  ...
  #pragma GCC diagnostic pop

For warnings you want to disable in a smaller scope. s/GCC/clang/ for clang. Bonus points:

  #define MM_WARNING_IGNORE_GCC(x)   MM_IF_GCC(   _Pragma(GCC   diagnostic ignored x) )
  #define MM_WARNING_IGNORE_CLANG(x) MM_IF_CLANG( _Pragma(clang diagnostic ignored x) )
  #define MM_WARNING_IGNORE_MSVC(x)  MM_IF_MSVC(  __pragma(warning(disable: x))       )
  #define MM_WARNING_PUSH() \
    IF_GCC(   _Pragma(GCC diagnostic push)   ) \
    IF_CLANG( _Pragma(clang diagnostic push) ) \
    IF_MSVC(  __pragma(warning(push))        )
  #define MM_WARNING_POP() \
    IF_GCC(   _Pragma(GCC diagnostic pop)   ) \
    IF_CLANG( _Pragma(clang diagnostic pop) ) \
    IF_MSVC(  __pragma(warning(pop))        )

  MM_WARNING_PUSH()
  MM_WARNING_IGNORE_GCC("-Wspecific-warning")
  MM_WARNING_IGNORE_CLANG("-Wspecific-warning")
  MM_WARNING_IGNORE_MSVC(1234)
  ...
  MM_WARNING_POP()

Defining MM_IF_*() is left as an exercise to the reader.

clang understands #pragma GCC diagnostic fine, no need to have special code for it.

Hmm. I could swear this wasn't the case in one of the build environments I ran into (possibly an older version of clang or something? or perhaps I'm thinking of some other non-diagnostic pragma...)

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