Add cpp_std option for Visual Studio C++ compiler

docs/markdown/Release-notes-for-0.46.0.md

@@ -21,3 +21,8 @@ Added the function `subdir_done()`. Its invocation exits the current script at
 the point of invocation. All previously invoked build targets and commands are
 build/executed. All following ones are ignored. If the current script was
 invoked via `subdir()` the parent script continues normally.
+
+## Added `cpp_std` option for the Visual Studio C++ compiler
+
+Allows the use of C++17 features and experimental not-yet-standardized
+features. Valid options are `c++11`, `c++14`, `c++17`, and `c++latest`.

mesonbuild/backend/vs2010backend.py

@@ -727,12 +727,13 @@ def gen_vcxproj(self, target, ofname, guid):
         file_args = dict((lang, CompilerArgs(comp)) for lang, comp in target.compilers.items())
         file_defines = dict((lang, []) for lang in target.compilers)
         file_inc_dirs = dict((lang, []) for lang in target.compilers)
+
         # The order in which these compile args are added must match
         # generate_single_compile() and generate_basic_compiler_args()
         for l, comp in target.compilers.items():
             if l in file_args:
                 file_args[l] += compilers.get_base_compile_args(self.get_base_options_for_target(target), comp)
-                file_args[l] += comp.get_option_compile_args(self.environment.coredata.compiler_options)
+                file_args[l] += comp.get_option_compile_args(self.get_compiler_options_for_target(target))
         # Add compile args added using add_project_arguments()
         for l, args in self.build.projects_args.get(target.subproject, {}).items():
             if l in file_args:

mesonbuild/compilers/cpp.py

@@ -207,10 +207,20 @@ def __init__(self, exelist, version, is_cross, exe_wrap, is_64):
         self.base_options = ['b_pch'] # FIXME add lto, pgo and the like
 
     def get_options(self):
+        c_stds = ['none', 'c++11']
+        # Visual Studio 2015 Update 3 and later
+        if version_compare(self.version, '>=19.10.25017'):
+            c_stds += ['c++14', 'c++latest']
+        # Visual Studio 2017 and later
+        if version_compare(self.version, '>=19.11'):
+            c_stds += ['c++17']
         return {'cpp_eh': coredata.UserComboOption('cpp_eh',
                                                    'C++ exception handling type.',
                                                    ['none', 'a', 's', 'sc'],
                                                    'sc'),
+                'cpp_std': coredata.UserComboOption('cpp_std', 'C++ language standard to use',
+                                                    c_stds,
+                                                    'none'),
                 'cpp_winlibs': coredata.UserArrayOption('cpp_winlibs',
                                                         'Windows libs to link against.',
                                                         msvc_winlibs)
@@ -221,6 +231,9 @@ def get_option_compile_args(self, options):
         std = options['cpp_eh']
         if std.value != 'none':
             args.append('/EH' + std.value)
+        std = options['cpp_std']
+        if std.value not in ['none', 'c++11']:
+            args.append('/std:' + std.value)
         return args
 
     def get_option_link_args(self, options):

test cases/windows/14 vs c++17/main.cpp

@@ -0,0 +1,7 @@
+[[nodiscard]] int foo() {
+    return 0;
+}
+
+int main() {
+    return foo();
+}

test cases/windows/14 vs c++17/meson.build

@@ -0,0 +1,8 @@
+project('wincpp', 'cpp')
+
+if meson.get_compiler('cpp').version().version_compare('<19.11')
+    error('MESON_SKIP_TEST Visual Studio 2017 (version 15.3) or later is required for C++17 support')
+endif
+
+exe = executable('prog', 'main.cpp', override_options: ['cpp_std=c++17'])
+test('wincpp', exe)