Use me like
#include <stdint.h>
#include <stdio.h>
#include "color.h"
int main(void) {
color_t color;
color.rgbw.r = 0x11;
color.rgbw.g = 0x22;
color.rgbw.b = 0x33;
color.rgbw.w = 0x44;
printf("%08x\n", color.u32);
printf("%02x%02x%02x%02x\n", color.arr[3], color.arr[2], color.arr[1], color.arr[0]);
printf("%02x%02x%02x%02x\n", color.rgbw.w, color.rgbw.b, color.rgbw.g, color.rgbw.r);
return 0;
}