Compiler extensions made portable.

compiler_ext.c

/*
 Compiler extensions made portable

 Usage:
 In MSVC, attributes must be on declarations in addition to prototypes.
 Use _ATTRIBUTES to conditionally declare them, depending on compiler.

 // Prototype
 EXT_warn_unused_result EXT_force_inline int SomeFunc( void );

 // Decl
 _ATTRIBUTES(EXT_warn_unused_result EXT_force_inline) int SomeFunc( void );
 \endcode
 
*/
    
    
#if defined(__GNUC__) && (__gnuc__ >= 4)
#define EXT_warn_unused_result __attribute__((warn_unused_result))
#define EXT_force_inline __attribute__((always_inline))
#define EXT_pure_function __attribute__((pure))
#define EXT_const_function __attribute__((const))
#define EXT_no_vtable
#define _ATTRIBUTES(x)

#elif defined(_MSC_VER) && (_MSC_VER >= 1700)
#define EXT_warn_unused_result _Check_return_
#define EXT_force_inline __forceinline
#define EXT_pure_function
#define EXT_const_function
#define EXT_no_vtable __declspec(novtable)
#define _ATTRIBUTES(x) x

#else
#define EXT_warn_unused_result
#define EXT_force_inline inline
#define EXT_pure_function
#define EXT_const_function
#define _ATTRIBUTES(x)

#endif