Is using #pragma warning push/pop the right way to temporarily alter warning level?

Question

Once in a while it\'s difficult to write C++ code that wouldn\'t emit warnings at all. Having warnings enabled is however a good idea. So it is often necessary to disable wa

Answer 1

The first method is the best way to do it, IMO. I know of no problems with it.

Simply bear in mind that a #pragma is compiler specific so don't expect it to work on every compiler out there :)

Answer 2

This will work with multiple compilers (and different versions of compilers).

Header "push"

#if defined(__clang__)
# pragma clang diagnostic push
#endif

#if defined(_MSC_VER)
# pragma warning(push)
#endif

#if defined(YOUR_FAVORITE_COMPILER)
# pragma your compiler push warning
#endif

Header "pop"

#if defined(__clang__)
# pragma clang diagnostic pop
#endif

#if defined(_MSC_VER)
# pragma warning(pop)
#endif

Some warning

#if defined(__clang__)
# pragma clang diagnostic ignored "-Wunused-parameter"
# pragma clang diagnostic ignored "-Wunused-variable"
#  if __has_warning("-Wnew-special-warning")
#   pragma clang diagnostic ignored "-Wnew-special-warning"
#  endif
#endif

#if defined(_MSC_VER)
# pragma warning(disable: 4100) // unreferenced formal parameter
# if _MSC_VER > _MSC_SOME_VERSION
#  pragma warning(disable: xxxx) // disable one more for special version
# endif
#endif

Usage

// This code reports warnings
// ...
#include <ignore_compiler_warning/push>
#include <ignore_compiler_warning/warning_type_1>
#include <ignore_compiler_warning/warning_type_2>
#include <ignore_compiler_warning/warning_type_3>
// This code ignores warnings type_{1,2,3}
// ...
#include <ignore_compiler_warning/pop>
// Back to reporting warnings
// ...

_{Additionally include guards can check that there is no double push/pop/disable-warning pragmas.}

Update

• Implementation
• List of available warnings
• CMake companion function to generate flags

Answer 3

Too late for sharptooth but for all the googlers out there:

#pragma warning ( suppress: ThatWarning )
// one single line with ThatWarning

is short for (generally since VS 2008, but in VS 2005 for Code Analyzer warnings only):

#pragma warning ( push )
#pragma warning ( disable: ThatWarning )
// one single line with ThatWarning
#pragma warning ( pop )

Answer 4

The correct approach (although a bit ugly)

#ifdef _MSC_VER
 #pragma warning( push )
 #pragma warning( once: ThatWarning )
#endif
 //code with ThatWarning here
#ifdef _MSC_VER
 #pragma warning( pop )
#endif

Answer 5

You can disable specific warnings in the project or file options and this setting applies as the 'default' per those #pragmas at the relevant scope. Some of the warnings in VS2005 are so useless/annoying that this cleans up the output quite a bit, if using /W4.

This is in Properties under Configuration Properties -> C/C++ -> Advanced.

Answer 6

The first approach allows you change the specific warning setting in a local scope. It first stores all the current warning state by push into stack, apply your warning modifications, then restore (pop) to last warning state.

#pragma warning( push ) #pragma warning( once: ThatWarning ) //code with ThatWarning here #pragma warning( pop )