Question on DLL Exporting/Importing and Extern on Windows

Question

I have some quick questions on windows dll.

Basically I am using the ifdefs to handle the dllexport and dllimport, my question is actually regarding the placement of

Answer 1

First, you don't need to import or export typedefs. As long as they're in the header files that both sides use, you're good. You do need to import/export functions and class definitions.

Presumably you use the same header files for both the importing and exporting code, so you could do some makefile magic to define a preprocessor macro on each side, then do something like this:

#if defined( LIBRARY_CODE )
#define MYAPI __declspec(dllexport)
#else
#define MYAPI __declspec(dllimport)
#endif

extern MYAPI void func1();
class MYAPI MyClass {
    ...
};

Regarding C vs. C++ functions, you can do this:

#if defined( __cplusplus__ ) // always defined by C++ compilers, never by C
#define _croutine "C"
#else
#define _croutine
#endif

extern _croutine void function_with_c_linkage();

Make sure you import this header file from your C++ source file (containing the implementation of this function) or the compiler won't know to give it C linkage.