qperr.hlp (Topic list)
Important Notice
The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.
Error Message
 
Error 133:  Real underflow
 
A floating-point operation produced an underflow. This
error only occurs if you are using the 8087 numeric
coprocessor with a control word that unmasks underflow
exceptions.