ANSI adopted function prototypes from C++ in C89. Originally C had no type checking on function parameters. All arguments were promoted to word width and pushed

ANSI adopted function prototypes from C++ in C89. Originally C had no type checking on function parameters. All arguments were promoted to word width and pushed to the stack. If you gave a function fewer arguments it would just read garbage off the end of the stack. If you gave it excess arguments they were silently ignored.