#include <math.h>
#include <setjmp.h>

jmp_buf mark;

double fdiv ( double a, double b );

int main ( void )
{
  int    jmpret;
  double r, n1 = 1.0, n2 = 0.0;

  jmpret = setjmp ( mark );      //违背1

  if ( 0 == jmpret )
  {
    r = fdiv ( n1, n2 );
  }
  else
  {
    return ( -1 );
  }

  return ( 0 );
}

double fdiv ( double a, double b )
{
  double div = a / b;

  if ( fabs ( b ) < 1e-10 )
  {
    longjmp ( mark, -1 );        //违背2
  }

  return div;
}