PRB: FLL Created Without LCK API Functions Is Invalid

• Microsoft Visual FoxPro for Windows, version 3.0

SYMPTOMS

You may receive the error message "Library file <filename> is invalid" when using the SET LIBRARY TO command to load an .fll file created with the Library Construction Kit (LCK).

CAUSE

There appears to be a problem with .fll files that are created for Visual FoxPro that don't call any of the _Functions that are part of the FoxPro API. This is not the case with .fll files created in previous versions. The error appears to be caused by the fact that the DLL doesn't have any exports. Normally a valid .fll file will contain the DispatchAPI export.

WORKAROUND

Call an extraneous .fll function in the code.

STATUS

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

MORE INFORMATION

Steps to Reproduce Problem

Create an .fll file but don't add any of the Library construction Kit functions besides the FoxTable and FoxInfo structures:

// include the library construction header file
#include <pro_ext.h>

void bugtest(ParamBlk  *parm) // the function definition
    {
     double c,e;
     c=3.00;
     e=++c*3.1415927;
     //_RetFloat(e,15,10);
     //Remove comment on previous line to fix error
    }

// the FoxInfo structure registers the function

     {"BUGTEST",(FPFI) bugtest, 0, ""},

// the FoxTable structure

     (FoxTable  *) 0, sizeof(myFoxInfo)/sizeof(FoxInfo), myFoxInfo