Test C program to illustrate where configure step fails

conf.c (text/plain), 1.60 KB, created by Stuart Hickinbottom on 2006-06-15 12:33:41 UTC

      #include <stdio.h>
      /* Why is this so damn hard? */
      #undef __GNUC__
      #undef __USE_ISOC99
      #define __USE_ISOC99
      #include <limits.h>
      int main(void) {
        long long i, llmin, llmax = 0;

        #if defined(LLONG_MIN) && defined(LLONG_MAX)
        fprintf(stderr, "Using system header for LLONG_MIN and LLONG_MAX\n");
        llmin = LLONG_MIN;
        llmax = LLONG_MAX;
        #else
        fprintf(stderr, "Calculating LLONG_MIN and LLONG_MAX\n");
        /* This will work on one's complement and two's complement */
        for (i = 1; i > llmax; i <<= 1, i++)
          llmax = i;
        llmin = llmax + 1LL;    /* wrap */
        #endif

	fprintf(stderr, "llmin:     %lld\n", llmin);
	fprintf(stderr, "llmin + 1: %lld\n", llmin + 1);
	fprintf(stderr, "llmin - 1: %lld\n", llmin - 1);
	fprintf(stderr, "llmax:     %lld\n", llmax);
	fprintf(stderr, "llmax + 1: %lld\n", llmax + 1);
	fprintf(stderr, "llmax - 1: %lld\n", llmax - 1);
        if (llmin + 1 < llmin) {
	  fprintf(stderr, "sanity fail: (llmin + 1 < llmin)\n");
	}

        if (llmin - 1 < llmin) {
	  fprintf(stderr, "sanity fail: (llmin - 1 < llmin)\n");
	}

        if (llmax + 1 > llmax) {
	  fprintf(stderr, "sanity fail: (llmax + 1 > llmax)\n");
	}

        if (llmax - 1 > llmax) {
	  fprintf(stderr, "sanity fail: (llmax - 1 > llmax)\n");
	}

        /* Sanity check */
        if (llmin + 1 < llmin || llmin - 1 < llmin || llmax + 1 > llmax || llmax - 1 > llmax) {
          fprintf(stderr, "sanity check failed\n");
          exit(2);
        }

        exit(0);
      }