extern-c

I have a C function that I would like to call from C++. I couldn't use " extern "C" void foo() " kind of approach because the C function failed to be compiled using g++. But it compiles fine using gcc. Any ideas how to call the function from C++? Compile the C code like this: gcc -c -o somecode.o somecode.c Then the C++ code like this: g++ -c -o othercode.o othercode.cpp Then link them together, with the C++ linker: g++ -o yourprogram somecode.o othercode.o You also have to tell the C++ compiler a C header is coming when you include the declaration for the C function. So othercode.cpp begins

Why do we need to use: extern "C" { #include <foo.h> } Specifically: When should we use it? What is happening at the compiler/linker level that requires us to use it? How in terms of compilation/linking does this solve the problems which require us to use it? C and C++ are superficially similar, but each compiles into a very different set of code. When you include a header file with a C++ compiler, the compiler is expecting C++ code. If, however, it is a C header, then the compiler expects the data contained in the header file to be compiled to a certain format—the C++ 'ABI', or 'Application

I know this. Calling C function from C++: If my application was in C++ and I had to call functions from a library written in C. Then I would have used //main.cpp extern "C" void C_library_function(int x, int y);//prototype C_library_function(2,4);// directly using it. This wouldn't mangle the name C_library_function and linker would find the same name in its input *.lib files and problem is solved. Calling C++ function from C??? But here I'm extending a large application which is written in C and I need to use a library which is written in C++. Name mangling of C++ is causing trouble here.