Writes output to a stream under format control, using a variable argument list.
#include <stdarg.h> #include <stdio.h> int vfprintf ( FILE *fp, const char *format, va_list arg);
(IN) Points to the file.
(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 vfprintf function writes output to the file pointed to by fp under control of the format parameter. The vfprintf function is equivalent to fprintf, with the variable arguments replaced with arg, which has been initialized by the va_start macro.