C + + Build DLLs and method instances that invoke DLLs _c language

I am based on the network of multiple related blog posts original

1) Build DLL

Create two files xxx.h, xxx.cpp

Xxx.h contents are as follows:

#ifdef Build_xxx_dll
#define EXPORT __declspec (dllexport)
#else
#define EXPORT __declspec (dllimport)
#endif

extern "C" {
EXPORT void example (void);
... ...
}

Xxx.cpp contents are as follows:

#define Build_xxx_dll
#include "xxx.h"

void Example (void)
{
}
... ...

Then compile from the DOS console (assuming that MinGW is installed and adding environment variables)
g++-shared-wl,--kill-at,--output-def,xxx.def-o xxx.dll xxx.cpp

(because C + + uses the Modifier function name to implement the function overload, we should use extern "C" with the--kill-at compilation option to avoid modifying the function name, the Build_xxx_dll macro function is used to select Function Prototype declaration function)

2 Static Calling DLL

Add the following content to the new document Yyy.cpp;
#include "xxx.h"
#pragma comment (lib, "Xxx.dll")

The generated DLL does not require DEF files and CPP files to Also
Without xxx.h, it is necessary to add the function prototype declaration in H file into Yyy.cpp

You need to join the DLL at compile time, similar to this:
g++-L-o yyy.exe yyy.cpp xxx.dll

3 Dynamic Call DLL

First, you need to include windows.h
#include <windows.h>

You need a handle. Save the loaded DLL file
HInstance hdll=loadlibrary ("Xxx.dll");

Declare the corresponding function pointer type of the desired function
typedef void (*PFUNC) (void);

To get a function pointer to a function
Pfunc pf= (pfunc*) GetProcAddress (hDLL, "example");

When you are finished using, release the DLL file
FreeLibrary (hDLL);