Question

I am developing a C program and have been stumped by this warning. I want to retrieve arguments from the list using va_arg.

args[i] = (int) va_arg(argptr, int); 

or

args[i] = (char) va_arg(argptr, char);

the problem that am getting this warning:

... void *' differs in levels of indirection from 'int'...

the same also for char case.
Any explanation for that?

code:

void test_function(va_list argptr, int (*callback)(),
                   int ret_typel)
{
  int i ;
  int arg_typel;
  int no_moreb = TRUE;
  void *args[MAX_FUNCTION_ARGS];
  for (i=0; no_moreb; i++) {
    arg_typel = (int)va_arg(argptr, int);
    switch(arg_typel) {
    case F_INT:
      args[i] = (int) va_arg(argptr, int);
      break;
    case F_CHAR:
      args[i] = (char) va_arg(argptr, char);
      break;
    default:
      no_moreb = FALSE;
      i--;
      break;
    }
  }
}

Answer 1

The problem is that args[] is an array of void *. You cannot assign an int or float to a void * (it doesn’t make any sense). You could get round this by casting, but it’s not a good idea.

If you want to store different types in the same variable, consider a union:

typedef union
{
    char  c;
    int   i;
    float f;
} MyUnion;

MyUnion args[MAX_FUNCTION_ARGS];

args[i].c = va_arg(argptr, char);
args[i].i = va_arg(argptr, int);
args[i].f = va_arg(argptr, float);

UPDATE
As Jonathan Leffler correctly points out in his answer, va_arg(argptr, char) and va_arg(argptr, float) should not be used, due to default promotions for variadic functions.