text: 
  #include <stdlib.h>
  #include <stdio.h>
  #include <string.h>
  #include "crypto_sign.h"
  
  char *msg = "Hello World";
  
  int main(int argc, char *argv[]) {
      unsigned char sk[SECRETKEYBYTES], vk[PUBLICKEYBYTES];
      unsigned char *sigmsg, *newmsg;
      unsigned long long sigmsglen, newmsglen;
      int ret;
      crypto_sign_keypair(vk, sk);
      printf("got keypair\n");
      sigmsg = malloc(strlen(msg)+1+BYTES);
      if (!sigmsg)
          return 1;
      crypto_sign(sigmsg, &sigmsglen, (unsigned char *)msg, strlen(msg)+1, sk);
      printf("got signature\n");
      if (sigmsglen != strlen(msg)+1+BYTES)
          return 2;
      newmsg = malloc(sigmsglen);
      if (!newmsg)
          return 3;
      ret = crypto_sign_open(newmsg, &newmsglen, sigmsg, sigmsglen, vk);
      printf("verified signature\n");
      if (ret == 0)
          printf("good!\n");
      else
          printf("bad\n");
      sigmsg[0] ^= 0x01;
      ret = crypto_sign_open(newmsg, &newmsglen, sigmsg, sigmsglen, vk);
      if (ret == 0) 
          printf("bad: failed to detect simple corruption\n");
      else
          printf("good: detected simple corruption\n");
      return 0;
  }
  