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author | Dylan Baker <dylan@pnwbakers.com> | 2021-08-08 16:29:01 -0700 |
---|---|---|
committer | Jussi Pakkanen <jpakkane@gmail.com> | 2021-08-11 21:54:16 +0300 |
commit | 0b97d585480e973d8b149618901f7a4ddfa1a906 (patch) | |
tree | 6d7641e277f9c7570a377635c1b5312f58aa535e | |
parent | 042adba204adeb8599e6ce516e0615f9a7b1f9c0 (diff) | |
download | meson-0b97d585480e973d8b149618901f7a4ddfa1a906.zip meson-0b97d585480e973d8b149618901f7a4ddfa1a906.tar.gz meson-0b97d585480e973d8b149618901f7a4ddfa1a906.tar.bz2 |
compilers/c++: Add MSVC option to make the __cplusplus define accurate
Otherwise it always returns the value for c++98, starting with MSVC 2017
15.7 or later. Earlier versions are not affected by this mis-feature
-rw-r--r-- | docs/markdown/snippets/msvc_cplusplus_define.md | 7 | ||||
-rw-r--r-- | mesonbuild/compilers/cpp.py | 11 | ||||
-rw-r--r-- | test cases/windows/18 msvc cplusplus define/main.cpp | 7 | ||||
-rw-r--r-- | test cases/windows/18 msvc cplusplus define/meson.build | 14 | ||||
-rw-r--r-- | test cases/windows/3 cpp/meson.build | 2 | ||||
-rw-r--r-- | unittests/windowstests.py | 1 |
6 files changed, 40 insertions, 2 deletions
diff --git a/docs/markdown/snippets/msvc_cplusplus_define.md b/docs/markdown/snippets/msvc_cplusplus_define.md new file mode 100644 index 0000000..eabfbe8 --- /dev/null +++ b/docs/markdown/snippets/msvc_cplusplus_define.md @@ -0,0 +1,7 @@ +## MSVC now sets the __cplusplus #define accurately + +For reasons, MSVC will always return `199711L` for `__cplusplus`, even when a +newer c++ standard is explicitly requested, unless you pass a specific option to +the compiler for MSVC 2017 15.7 and newer. Older versions are unaffected by +this. Meson now always sets the option if it is available, as it is unlikley +that users want the default behavior. diff --git a/mesonbuild/compilers/cpp.py b/mesonbuild/compilers/cpp.py index 44155d1..057a39a 100644 --- a/mesonbuild/compilers/cpp.py +++ b/mesonbuild/compilers/cpp.py @@ -692,6 +692,17 @@ class VisualStudioCPPCompiler(CPP11AsCPP14Mixin, VisualStudioLikeCPPCompilerMixi del args[i] return args + def get_always_args(self) -> T.List[str]: + args = super().get_always_args() + + # update the __cplusplus #define to match the version given on the + # command line with /std:NNN, but only for versions above 15.7 (2017) + # https://docs.microsoft.com/en-us/cpp/build/reference/zc-cplusplus?view=msvc-160 + if version_compare(self.version, '>= 15.7'): + args.append('/Zc:__cplusplus') + + return args + class ClangClCPPCompiler(CPP11AsCPP14Mixin, VisualStudioLikeCPPCompilerMixin, ClangClCompiler, CPPCompiler): def __init__(self, exelist: T.List[str], version: str, for_machine: MachineChoice, is_cross: bool, info: 'MachineInfo', target: str, diff --git a/test cases/windows/18 msvc cplusplus define/main.cpp b/test cases/windows/18 msvc cplusplus define/main.cpp new file mode 100644 index 0000000..bc0b1fd --- /dev/null +++ b/test cases/windows/18 msvc cplusplus define/main.cpp @@ -0,0 +1,7 @@ +int main() { +#if __cplusplus == 199711L + return 1; +#else + return 0; +#endif +} diff --git a/test cases/windows/18 msvc cplusplus define/meson.build b/test cases/windows/18 msvc cplusplus define/meson.build new file mode 100644 index 0000000..92cf316 --- /dev/null +++ b/test cases/windows/18 msvc cplusplus define/meson.build @@ -0,0 +1,14 @@ +project('msvc __cplusplus', 'cpp', default_options : ['cpp_std=c++14']) + +cpp = meson.get_compiler('cpp') + +if cpp.get_id() != 'msvc' + error('MESON_SKIP_TEST: test is only relavent for msvc') +elif meson.project_version().version_compare('< 15.7') + error('MESON_SKIP_TEST: test is only relavent for msvc versions >= 15.7') +endif + +test( + 'main', + executable('main', 'main.cpp'), +) diff --git a/test cases/windows/3 cpp/meson.build b/test cases/windows/3 cpp/meson.build index 7b8080e..a9e6569 100644 --- a/test cases/windows/3 cpp/meson.build +++ b/test cases/windows/3 cpp/meson.build @@ -1,4 +1,4 @@ -project('wincpp', 'cpp') +project('wincpp', 'cpp', default_options : ['cpp_std=c++14']) exe = executable('prog', 'prog.cpp') test('wincpp', exe) diff --git a/unittests/windowstests.py b/unittests/windowstests.py index 9359642..f2517f2 100644 --- a/unittests/windowstests.py +++ b/unittests/windowstests.py @@ -359,4 +359,3 @@ class WindowsTests(BasePlatformTests): raise SkipTest('C++ modules are only supported with VS 2019 Preview or newer.') self.init(os.path.join(self.unit_test_dir, '86 cpp modules')) self.build() - |