orangepi cross compile on linux x86 desktop

orangepi_crosscompile.txt

//
// cross compiling on linux
// download compiler from https://imola.armbian.com/dl/_toolchain/
//   gcc-arm-11.2-2022.02-x86_64-aarch64-none-linux-gnu.tar.xz
// extract compiler

// compile on linux host (assumes x86) 
//     bin/aarch64-none-linux-gnu-gcc gpio.c
//     this will produce a.out

// copy to orangepi
//   scp a.out [email protected]:/home/orangepi/a.out
//   orangepi password is orangepi for user orangepi and root
//
// go to orangepi
//   ssh [email protected] (password: orangepi)
//   execute sudo ./a.out (pin 70 should blink)
//
// assuming root
// echo 70 > /sys/class/gpio/export
// echo out > /sys/class/gpio/gpio70/direction

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>

int main(){
int fs_value=open("/sys/class/gpio/gpio70/value",O_WRONLY);
for(int i=0; i<5; i++){
  write(fs_value,"1",1);
  sleep(1);
  write(fs_value,"0",1);
  sleep(1);}
  close(fs_value);
}