test.c

#include <emscripten.h>
// #include <stdio.h>
#include <stdlib.h>

char str[] = "Function from C (Web Assemblly) called!";

EMSCRIPTEN_KEEPALIVE
char* functionFromC () {
  return &str[0];
}

EMSCRIPTEN_KEEPALIVE
double loadTest () {
  // clock_t start, end;
  int start, end;
  double cpu_time_used;
  int num = 1, primes = 0;
  int limit = 150000;

  // don't work
  // start = emscripten_get_now();

  for (num = 1; num <= limit; num++) { 
      int i = 2; 
      while(i <= num) { 
          if(num % i == 0)
              break;
          i++; 
      }
      if(i == num)
          primes++;
  }
  return  primes;
}