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 _fpreset()              Reinitialize Floating-Point Math Package

 #include   <float.h>

 void       _fpreset(void);

    _fpreset() reinitializes the floating-point math package.

    Returns:    Nothing.

      Notes:    A program that traps floating-point error signals
                (SIGFPE, defined in <signal.h>) with signal() can safely
                recover from floating-point errors by invoking _fpreset()
                and doing a longjmp().

                On versions of MS-DOS prior to 3.0, a child process
                executed by system(), exec(), or spawn() that used the
                8087/80287 coprocessor could affect the floating-point
                state of the parent process if a numeric coprocessor was
                used.  The following precautions are recommended when
                using an 8087 or 80287:

                exec...(), spawn...(), or system() should not be called
                during the evaluation of a floating-point expression, and

                _fpreset() should be called after the child process
                finishes if there is a possibility that any 8087 or 80287
                floating-point operations were performed.

 Portability:   Applies to MS DOS only.

   -------------------------------- Example ---------------------------------

           #include <stdio.h>
           #include <signal.h>
           #include <setjmp.h>
           #include <float.h>

           int fphandler();
           jum_buf mark;
           double a = 1.0, b = 0.0, c;

           main()
           {
               if (signal(SIGFPE,fphandler) == (int(*) ())-1)
                       abort();
                if (setjmp(mark) == 0) {
                      c = a/b;
                      printf("Should never get here\n");
                }
                printf("Recovered from floating-point error\n");
           }

            int fphandler(sig,num)
            int sig,num;
            {
                printf("signal = %d  subcode = %d\n",sig,num);
                _fpreset();
                longjmp(mark,-1);
            }