What is the limitation of number of arguments in printf and how does variable arguments work?

Determining the number of arguments comes from the OS culture. Mainframes marked the last one by setting its high bit on, all the others were off. MS-DOS passed the number of arguments in the cx register. In the Unix culture, there is no convention for passing the number of arguments. It is a deficiency, oversight, weakness. You can pass the number of arguments explicitly as the last argument i.e. first on the stack, but that's not a commonly used convention. Printf() does it by counting the number of tokens in the format string and hoping the programmer passed the same number of arguments. When counts don't match, you have a bug and a corrupted stack. Even when they do, there's no way to make them typesafe. In C++, the logical solution would be passing the argument list as a collection. That's not done because it would be too slow and would create a chicken-and-egg problem for collection methods. The solution is depending on the compiler to be smart enough to count tokens in the printf() format string. That's fine for printf, but does nothing for user functions with variable arguments. Chalk it up to a Unix cultural deficiency with no solution.