Is it possible to have a variadic function in C with no non-variadic parameter?

Question

I have the following function:

void doStuff(int unusedParameter, ...)
{
    va_list params;
    va_start(params, unusedParameter);
    /* ... */
    va_end(p         


        

Answer 1

In GCC, you have a workaround: You can define a macro with a variable number of arguments and then add the dummy parameter in the expansion:

#define doStuff(...) realDoStuff(0, __VA_ARGS__)

Answer 2

Your choice is either leave it as it is and use va_list, alias it (if it's GCC) as others pointed out, or do something along the lines of exec(2) interface - passing an array of pointers requiring a NULL terminator:

/* \param args  NULL-terminated array of
 *              pointers to arguments.
 */
void doStuff( void* args[] );

Either way it would be much better to refactor the interface to somehow take advantage of the type system - maybe overload on exact argument types used:

void doStuff( int );
void doStuff( const std::string& );
void doStuff( const MyFancyAppClass& );

Hope this helps.