Random float in C using getrandom

I'm trying to generate a random floating point number in between 0 and 1 (whether it's on [0,1] or [0,1) shouldn't matter for me). Every question online about this seems to involves the rand() call, seeded with time(NULL), but I want to be able to invoke my program more than once a second and get different random numbers every time. This lead me to the getrandom syscall in Linux, which pulls from /dev/urandom. I came up with this:

#include <stdio.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <stdint.h>

int main() {
  uint32_t r = 0;
  for (int i = 0; i < 20; i++) {
    syscall(SYS_getrandom, &r, sizeof(uint32_t), 0);
    printf("%f\n", ((double)r)/UINT32_MAX);
  }
  return 0;
}

My question is simply whether or not I'm doing this correctly. It appears to work, but I'm worried that I'm misusing something, and there are next to no examples using getrandom() online.