/* With GCC/RAISONANCE, small printf (option LD Linker->Libraries->Small printf
set to 'Yes') calls __io_putchar() */
#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)
#define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)
#endif /* __GNUC__ */
Can some one explain to me; what's the relationship between __io_putchar and fputc? are they from stand C library? and how it is related to printf() that is used in USART comunications? thanks a lot.