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Q43899: Floating-Point Errors in QB.EXE with Coprocessor; Use SET NO87

Article: Q43899
Product(s): See article
Version(s): 4.00 4.00b 4.50
Operating System(s): MS-DOS
Keyword(s): ENDUSER | SR# S890419-109 B_BasicCom | mspl13_basic
Last Modified: 15-DEC-1989

When floating-point errors occur while a program is running in either
the QuickBASIC environment or as a compiled .EXE file, and the machine
is equipped with a math coprocessor, the problem may be due to the
configuration of the math coprocessor.

Math coprocessor problems can be identified by testing QuickBASIC with
the coprocessor disabled. To disable the coprocessor, SET the NO87
environment variable at the MS-DOS command prompt. This action must be
performed before QuickBASIC is invoked and not with a SHELL from the
editor. The MS-DOS command is as follows:

   SET NO87=Coprocessor is Disabled for QuickBASIC

This command disables the coprocessor for QuickBASIC. The string,
"Coprocessor is Disabled for QuickBASIC," may be any string with one
or more characters. If no characters follow the SET NO87= command, the
coprocessor is turned back on.

If the errors no longer occur after SETting the NO87 variable, then
the coprocessor should be checked for correct installation and
configuration.

This information applies to Microsoft QuickBASIC Versions 4.00, 4.00b,
and 4.50, Microsoft BASIC Compiler Versions 6.00 and 6.00b, and
Microsoft BASIC PDS Version 7.00.

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