Do i need to modify 'c' source to make it compitable with c++ application ?

[ankit vinayaka]

hello ,
I am using ' qt ' for gui frontend for my crypography based program that uses openssl ( 'c' ) library . Do i need to make any kind of major / minor changes to my orignal 'c' program if use qt that is written in c++ ?

[Banfa]

As long as your original program was written to exposed some sort of interface for its main tasks you should easily be able to write a C++/QT wrapper that makes those same function calls. Continue compiling your old C code as C and compile the new C++ code as C++.

In you header files declaring the C API you will need to mark the functions in your C code as using the C as opposed to the C++ calling convention. The usual method is to have in the header file

#ifdef __cplusplus
extern "C" {
#endif

// Declarations of functions in C source files

#ifdef __cplusplus
}
#endif

This tells the C++ compiler that those functions do not have the mangled (by the compiler) C++ function names but use C function names.

[ankit vinayaka]

Thanks for the reaply .

[donbock]

Certain C99 features are not supported by C++ (long long int, restrict, variadic macros, etc).

Certain more common C features are not supported by C++ (implicit cast to and from void*, K&R-style function declarations, use of "__" in variable names, etc).

Certain C features work differently in C++ (library function prototypes differ, C++ keywords can't be used as variable names, etc).

Take a look at this.