preprocessor define with #pragma directive

Question

I would like to do a #define which contains a #pragma directive but I got the following error. Any idea?

#define FunctionPar_Begin  typedef struct fpar { #pragma pack(4)

error C2121: '#': invalid character: possibly the result of a macro expansion

You should be able to use [`_Pragma("pack(4)")`](https://en.cppreference.com/w/cpp/preprocessor/impl). — Eljay, Oct 13 '22 at 17:12

score 1 · Answer 1 · answered Oct 13 '22 at 17:21

The one you probably want:

#define FunctionPar_Begin  typedef struct fpar { _Pragma("pack(4)")

MSVC also allows for:

#define FunctionPar_Begin  typedef struct fpar { __pragma(pack(4))

Clang/gcc also allow:

#define FunctionPar_Begin  typedef struct fpar { __attribute__((packed, aligned(4)))

1 Answers1