PRB: C2106 Using FP_SEG() and FP_OFF(), Header File Missing

ID: Q26588

5.00 5.10 6.00 6.00a 6.00ax 7.00 | 5.00 5.10 6.00 6.00a | 1.00 1.50

MS-DOS                           | OS/2                 | WINDOWS

kbtool kbprb

The information in this article applies to:

Microsoft C for MS-DOS, versions 5.0, 5.1, 6.0, 6.0a, and 6.0ax
Microsoft C for OS/2, versions 5.0, 5.1, 6.0, and 6.0a
Microsoft C/C++ for MS-DOS, version 7.0
Microsoft Visual C++ for Windows, versions 1.0 and 1.5

SYMPTOMS

An attempt to use the FP_SEG() or FP_OFF() macros fails and the compiler generates:

   error C2106: ' = ' : left operand must be l-value

CAUSE

The application uses _FP_SEG() or _FP_OFF as an l-value, but does not

#include the DOS.H header file.

When the source code does not include the DOS.H header file, the compiler treats FP_SEG() and FP_OFF() as function calls instead of macro definitions. The C2106 error occurs because a function is not an lvalue.

RESOLUTION

Modify the source code to #include the DOS.H header file

Additional reference words: 1.00 1.50 6.00 6.00a 6.00ax 7.00 8.00 8.00c KBCategory: kbtool kbprb KBSubcategory: CLIss Keywords : kb16bitonly

Last Reviewed: July 18, 1997