The util_vsprintf function formats a specified string, using a specified format, into a specified buffer using the vprintf-style syntax without bounds checking. It returns the number of characters in the formatted buffer.
For more information, see the documentation on the printf function for the runtime library of your compiler.
int util_vsprintf(char *s, register char *fmt, va_list args);
The number of characters formatted into the buffer.
char *s is the buffer to receive the formatted string.
register char *fmt is the format string. The function handles only %d and %s strings; it does not handle any width or precision strings.
va_list args is an STD argument variable obtained from a previous call to va_start.