Writes output to stdout under format control, using a variable argument list.
#include <stdio.h> int vprintf ( const char *format, va_list arg);
(IN) Points to the format control string. See Print Format Control Strings.
(IN) Specifies a variable argument list. The number of arguments is determined by the format string.
If successful, returns the number of characters written. If an output error occurred, returns a negative value and sets errno to one of the following:
The vprintf function writes output to the file stdout under control of the format parameter. The vprintf function is equivalent to printf, with the variable arguments replaced with arg, which has been initialized by the va_start macro.