primegen - enumerate small primes #include <primegen.h> void primegen_init(&pg);

uint64 primegen_next(&pg);

uint64 primegen_peek(&pg);

uint64 primegen_count(&pg,bound);

void primegen_skipto(&pg,bound); struct primegen pg;

uint64 bound;

The primegen library generates prime numbers in order: 2, 3, 5, 7, etc. It can generate primes as large as 10^15. The simplest way to use primegen is to call primegen_init and then call primegen_next repeatedly. The first call to primegen_next will return 2; the next call will return 3; the next call will return 5; and so on. At each moment the next few primes to be returned by primegen_next are buffered inside pg . primegen_init initializes pg with the first few primes, starting at 2. You must initialize pg with primegen_init before using pg with any of the other primegen routines. You may call primegen_init again to start over at 2. primegen_next returns the next buffered prime and removes that prime from pg . primegen_peek returns the next buffered prime but does not change pg . primegen_skipto discards all primes up to bound . It has the same effect as .EX while (primegen_peek(&pg) < bound) primegen_next(&pg); primegen_count discards all primes up to bound and returns the number of primes discarded. You can set up several independent generators; all primegen data is stored in pg . Beware, however, that each struct primegen uses quite a bit of memory. primes(1), primespeed(1)