Can I use shared library created in C++ in a C program?

Question

I am creating programs using C. However, I require to use a lot of libraries that have API\'s only for C++. So, is it possible that I can create a shared object in C++ and t

Answer 1

This is entirely possible. Here is how, quickly: 1.) You have a header.h with a C API that doesn't include any Cplusiness.

#ifndef MIXEDCCPP_H
#define MIXEDCCPP_H

#ifdef __cplusplus
extern "C" {
#endif
#include  // Any C-compatible headers will go here.

// C API goes here.  C Functions can't contain any CPPiness.
void myclass_setName( void *pClassObj, const char *pName, int nameLen );

#ifdef __cplusplus
}
#endif

#ifdef __cplusplus

// Stuff that is only compatible with CPP goes here
// __cplusplus section won't get processed while compiling C files.

#include  // CPP headers.


class MyClass {
   // Classes etc.
};
#endif // #ifdef __cplusplus

#endif // MIXEDCCPP_H

Then in the .cpp, you simply create some C-API functions that can even include CPP right in them:

#include "mixedccpp.h"

extern "C" {
// C API goes here.  C Functions can't contain any CPPiness in their prototypes.
void myclass_setName( void *pClassObj, const char *pName, int nameLen )
{
    // But CPP knowledge can go inside the function - no problem, since this is a CPP file.
    MyClass *pMyClass = static_cast(pClassObj);
    pMyClass->setName( pName, nameLen );
}

} // #extern "C"


// CPP Stuff goes here... or vice-versa.

In your case, you don't actually need any CPP code declared in your header since you are calling external libraries. But you need to create C-compatible functions in your CPP file which can call out to CPP libraries. Use extern "C" for those functions that need to be called from C files, and then use C-structs instead of classes and, if classes are needed, use void * to point to them and then cast them back to their class from the C function any time you need to access them. A standard makefile should be able to compile this just fine, assuming it compiles .cpp files as .cpp and understands extern "C" {}