Cross-platform code label macro? - c++

Question

In MSVC & C#, #pragma region can be used to label a code section.
Similarly, in GCC/Clang, #pragma mark can accomplish the same thing.
Is it possible to define a single macro such as CODELABEL(label) which will work for both compilers?
Basically, I'd like to avoid having to do the following:
#ifdef _WIN32
#pragma region Variables
#else
#pragma mark Variables
#endif
bool MyBool;
int MyInt;
#ifdef _WIN32
#pragma region Methods
#else
#pragma mark Methods
#endif
void MyMethod();
void AnotherMethod();
... and instead, do something like this:
CODELABEL( Variables )
bool MyBool;
int MyInt;
CODELABEL( Functions )
void MyMethod();
void AnotherMethod();
Is something like this possible?

Answer 1

Yes, in C++11, you can use _Pragma, since using #pragma in a macro definition is not allowed:
#ifdef _WIN32
#define PRAGMA(x) __pragma(x) //it seems like _Pragma isn't supported in MSVC
#else
#define PRAGMA(x) _Pragma(#x)
#endif
#ifdef _WIN32
#define CODELABEL(label) PRAGMA(region label)
#else
#define CODELABEL(label) PRAGMA(mark label)
#endif
The dance with PRAGMA is to satisfy _Pragma requiring a string literal, where side-by-side concatenation of two string literals (e.g., "mark" "section label") doesn't work.

Answer 2

According to this topic, the following should work.
#define STR_HELPER(x) #x
#define STR(x) STR_HELPER(x)
#ifdef _WIN32
#define LABEL region
#else
#define LABEL mark
#endif
and then
#pragma STR(LABEL) Variables
bool MyBool;
int MyInt;
#pragma STR(LABEL) Functions
void MyMethod();
void AnotherMethod();

Answer 3

As far as Windows and macOS are concerned, since Xcode 12 and Visual Studio 2019, you can easily use this syntax that works ok on both platforms:
#pragma region mark -
#pragma region mark Whathever Your Label
Xcode silently ignores the 'region' token while VS takes the 'mark' token as part of the label, which is a minor cosmetic issue, IMHO.