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out of date.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 134: Undefined external
A subprogram has been declared external, but it was not
defined by any of the .OBJ files linked in with the
program.