Question

To compile some legacy code A.c , which has a function prototype

void somefun(...)

gcc 4.1.2 always tell an error

 error: ISO C requires a named argument before ...

But I can not modify the code, so what C dialet option should I use to let GCC compile this code?

gcc -c A.c ????

Answer 1

I don’t think any of the C dialects in GCC accept this, but G++ does. What you can do is put the function definition in an extern "C" {} block and compile the module containing it with g++ (assuming it’s also a valid C++ function).

You must then declare it in C with void somefun() (K&R style).

This will require linking with g++ as well, though.

If C++ linkage is not what you want, then you should change the function to take no arguments and declare it in K&R style.