PlatformIO Community

Redirecting the iostream

My goal is to redirect the stdio and iostream to my UART.

My main.cpp is pretty simple:

#include <uart.h>
#include <iostream>

int main() {
    uart_init();

    while (true) {
        std::cout << "test" << std::endl;
        for (int i = 0; i < 180000; ++i);
    }
}

I would expect to have to include something like:

#include <stdio.h>

int fputc(int ch, FILE *f)
{
    uart_write(static_cast<char>(ch));
    return ch;
}

But the project builds without it and not surprisingly doesn’t output anything as it doesn’t know which IO to use.

My platformio.ini:

[env:disco_f407vg]
platform = ststm32
board = disco_f407vg
framework = cmsis
upload_protocol = jlink
debug_tool = jlink
build_flags = -O0 --specs=nano.specs
build_type = debug

I thought for GCC you’d have to implement _write()? Have you tried https://electronics.stackexchange.com/a/279945/158783?