How to retarget printf() on an STM32F10x?

Question

I use this code for retarget printf(), but it does not work

#ifdef __GNUC__
/* With GCC/RAISONANCE, small printf (option LD Linker->Libraries->         


        

Answer 1

Try hijacking the _write function like so:

#define STDOUT_FILENO   1
#define STDERR_FILENO   2

int _write(int file, char *ptr, int len)
{
    switch (file)
    {
    case STDOUT_FILENO: /*stdout*/
        // Send the string somewhere
        break;
    case STDERR_FILENO: /* stderr */
        // Send the string somewhere
        break;
    default:
        return -1;
    }
    return len;
}