Is there an alternative to using time to seed a random number generation?

Question

I\'m trying to run several instances of a piece of code (2000 instances or so) concurrently in a computing cluster. The way it works is that I submit the jobs and the clust

Answer 1

Windows

Provides CryptGenRandom() and RtlGenRandom(). They will give you an array of random bytes, which you can use as seeds.

You can find the docs on the msdn pages.

Linux / Unixes

You can use Openssl's RAND_bytes() to get a random number of bytes on linux. It will use /dev/random by default.

Putting it together:

#ifdef _WIN32
  #include 
#else
  #include  
#endif

uint32_t get_seed(void)
{
  uint32_t seed = 0;

#ifdef _WIN32
  RtlGenRandom(&seed, sizeof(uint32_t) );
#else
  RAND_bytes(&seed, sizeof(uint32_t) ); 
#endif

  return seed;
}

Note that openssl provides a Cryptographically secure PRNG by default, so you could use it directly. More info here.