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// ---- .h  -------
// when this header is included from a .cpp file, you have both the C++ and C API available
// including from a .c file gives you the C API only
// C++ API declarations
#ifdef __cplusplus   // compiled as C++ ==>
class CFoo 
{
  public:
    int Foo() { return ... };
    static CFoo * CreateInstance() { return new CFoo; }
};
 
#endif               // <== compiled as C++

// C API declarations
#ifdef __cplusplus   
extern "C" { // when compiling with C++, we explicitely say this has "C" linkage ==> 
#endif
void * FooCreate();
int FoFoo(void *);
#ifdef __cplusplus
} // extern "C"  // <== C linkage ends here 

#endif
 
// ---- .cpp ----------
// this file implements both the C++ and C API
// normal C++ implementation - in this example nothing, cause it's all in the header

// Now, implementing the functions with C linkage
// note that, though the functions are declared "extern "C", you can call C++ stuff
extern "C" void * FooCreate() { return (void *) CFoo::CreateInstance(); }
extern "C" int FooFoo(void * f) { return ((CFoo *)f)->Foo(); }
 

1. If it is free, and comes with advertisment, it's advertisement, but not free
2. If it's free, and it's crap, it's free crap.
3. If it's free and doesn't come with religion or propaganda, it's probably beer.
4. The world is not fair. See, how could it be more fair than you make it?
5. The world is full of marvels, every second contains a microchip
6. Don't explain as malice what can be explained as stupidity. Really, your paranoia is so yesterday.
7. Just because you can doesn't mean you have to. It's your choice, after all.
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9. The average rolle of a die is 3.5