PRB: Functions of the VC++ WPL May Not Respond as Expected

• Microsoft Visual FoxPro for Macintosh, version 3.0b

SYMPTOMS

When building a library of C functions to access with Visual FoxPro for Macintosh (with the SET LIBRARY Command), you may choose to use the Microsoft Visual C++ (VC++) compiler, which offers a set of functions (the Windows Portability Library, or WPL) that may be ported to the Macintosh. These functions may not work as expected or desired when loaded under Visual FoxPro for Macintosh.

CAUSE

Visual FoxPro for Macintosh was not designed to work with the functions of the Windows Portability Library. Many of these functions allocate memory outside of FoxPro, which is something that is not recommended within a library that will be loaded from FoxPro.

WORKAROUND

Use functions provided in the FoxPro API Library or the Mac Toolbox.

You may also be able to create a stand-alone application, using the functions of the Windows Portability library, that may be run from Visual FoxPro via AppleScript, using the FoxPro RUNSCRIPT command.

STATUS

Microsoft is researching this behavior and will post more information in the Microsoft Knowledge Base as it becomes available.