Test matherr

test-matherr.c

// see also:
// http://msdn.microsoft.com/ja-jp/library/k3backsw.aspx
// http://linuxjm.sourceforge.jp/html/LDP_man-pages/man3/matherr.3.html

#define _SVID_SOURCE
#include <math.h>
#include <string.h>
#include <stdio.h>

#ifdef _WIN32
#define matherr _matherr
#define exception _exception
#endif

int main(int argc, char **argv)
{
#ifdef __linux__
  _LIB_VERSION = _SVID_;
#endif

  printf("log(-2.0)   = %e\n", log(-2.0));
  printf("log10(-5.0) = %e\n", log10(-5.0));
  printf("log(0.0)    = %e\n", log(0.0));

  return 0;
}

int matherr(struct exception *e)
{
  if (e->type == DOMAIN) {
    if (strcmp(e->name, "log") == 0)
    {
      e->retval = log(-(e->arg1));
      fprintf(stderr, "Special: using absolute value: %s: _DOMAIN error\n", e->name);
      return 1;
    }
    else if (strcmp(e->name, "log10") == 0)
    {
      e->retval = log10(-(e->arg1));
      fprintf(stderr, "Special: using absolute value: %s _DOMAIN error\n", e->name);
      return 1;
    }
  }
  fprintf(stderr, "Normal: ");
  return 0;
}