I am trying to figure out how to use the printf function to print to the serial port.
I see in stdio.h that the printf prototype is defined as:
int _EXFUN(printf, (const char *__restrict, ...) _ATTRIBUTE ((__format__ (__printf__, 1, 2))));
What does it mean? Where is the exact location of this function definition? What would be general point of finding out how to use this kind of function to output?