fusl/src/prng/rand_r.c

#include <stdlib.h>

static unsigned temper(unsigned x) {
  x ^= x >> 11;
  x ^= x << 7 & 0x9D2C5680;
  x ^= x << 15 & 0xEFC60000;
  x ^= x >> 18;
  return x;
}

int rand_r(unsigned* seed) {
  return temper(*seed = *seed * 1103515245 + 12345) / 2;
}