matherr() Traps Floating-Point Errors Only in Library

MS-DOS                      | OS/2            | WINDOWS

The information in this article applies to:

• The C Run-time (CRT), included with:

      - Microsoft C for MS-DOS, versions 5.1, 6.0, 6.0a, and 6.0ax
      - Microsoft C for OS/2, versions 5.1, 6.0, and 6.0a
      - Microsoft C/C++ for MS-DOS, version 7.0
      - Microsoft Visual C++ for Windows, versions 1.0, 1.5, 1.51, and 1.52
  

SUMMARY

The matherr() function in the Microsoft C run-time library does not trap floating-point errors in application code. This function traps floating-point errors generated by functions in the run-time library. For example, when the following sample application generates an arithmetic overflow error, the system matherr() routine displays a message and terminates the program.

MORE INFORMATION

To trap floating-point errors in application code, such as the overflow error above, use the signal() function to process the SIGFPE interrupt.

Sample Code

   #include <math.h>

   int matherr(struct exception *x)
   {
      x->retval = 2;
      return 1;
   }

   void main(void)
   {
      double f;

      f = 2.0;

      while (1)
         f *= f;
   }

REFERENCES

For more information on the signal() function, see the Microsoft C Run-Time Library Reference.