Keil serial port redirection

Macro definition method

#include "stdio.h"

/* ------------------ Redirect printf Function mapping to serial port 1 On -------------------*/
#if !defined(__MICROLIB)

//#pragma import(__use_no_semihosting)
__asm (".global __use_no_semihosting\n\t");
void _sys_exit(int x) // Avoid using half host mode 
{
  x = x;
}
//__use_no_semihosting was requested, but _ttywrch was 
void _ttywrch(int ch)
{
    ch = ch;
}
struct __FILE
{
  int handle;
};
FILE __stdout;

#endif

#if defined ( __GNUC__ ) && !defined (__clang__) 
#define PUTCHAR_PROTOTYPE int __io_putchar(int ch)
#else
#define PUTCHAR_PROTOTYPE int fputc(int ch, FILE *f)
#endif 
PUTCHAR_PROTOTYPE
{
  /*  Realize the function of sending a byte of data through the serial port  */
  //serial_write(&serial1, (uint8_t)ch); // Send your own data to the serial port 
	HAL_UART_Transmit(&huart1, (uint8_t *)&ch, 1, 0xFFFF);
    return ch;
}