Article: Q222676
Product(s): Microsoft FoxPro
Version(s): WINDOWS:6.0
Operating System(s):
Keyword(s): kbCOMt kbvfp600 kbVS600sp2 kbVS600sp3
Last Modified: 20-MAY-1999
-------------------------------------------------------------------------------
The information in this article applies to:
- Microsoft Visual FoxPro for Windows, version 6.0
-------------------------------------------------------------------------------
SUMMARY
=======
Starting with the Visual Studio 6.0 Service Pack 3 version of Visual FoxPro 6.0,
you now have the ability to create multi-threaded DLL COM components. There is
no obvious way to tell from the DLL file itself or its Property Sheet whether a
DLL is single-threaded or multi-threaded. This article demonstrates a technique
for determining whether a particular DLL is single- or multi-threaded.
MORE INFORMATION
================
This approach uses the FILETOSTR() function to transfer the contents of the DLL
to be tested into a string variable, then searches for the text "foxwt" or
"foxwd" within the string. The "foxwt" text will be contained in a
multi-threaded DLL and the "foxwd" text will be contained in a single- threaded
DLL.
The program below is an implementation of this approach. You can pass it a DLL
name if you want, or it will prompt you for a file to test.
It correctly calls a Visual FoxPro 5.0 or Visual FoxPro 6.0 pre-SP3 DLL
"single-threaded."
The program calls DLLs not built in Visual FoxPro "Non-FoxPro" DLLs.
STEPS TO USE THE PROGRAM
------------------------
1. Save the following code in a file called TestADLL.PRG:
****************************
* Program TestADLL.PRG
*
* Parameters:
* tcFileName - Name of DLL file w/ or w/o extension
*
* Usage: DO TestADLL with <dllname>
*
* OR
*
* DO TestADll
* Prompts for file name
*
****************************
#DEFINE MSGBOXTITLE 'VFP COM DLL Tester'
LPARA tcFileName, p2, p3, p4, p5, p6
LOCAL lcType, lcFileContents
* Parameter checking/cleanup
DO CASE
CASE PARA() > 1
MESSAGEBOX([Too many parameters specified. Usage is:] + ;
CHR(13)+CHR(13) + ;
[DO TestDLL with 'filename'], 16, MSGBOXTITLE)
RETURN
CASE PARA() = 0
tcFileName = GETFILE('dll','Open a DLL' , ;
'Open', 0, 'Select a DLL to check')
IF EMPTY(tcFileName)
RETURN
ENDIF
CASE VARTYPE(tcFileName) # 'C'
MESSAGEBOX([Incorrect parameter data type. Usage is:] + ;
CHR(13)+CHR(13) + ;
[DO TestDLL with 'filename'], 16, MSGBOXTITLE)
RETURN
ENDCASE
* Drop trailing dot, if present
IF ATC('.', tcFileName) = LEN(tcFileName)
tcFileName = STRTRAN(tcFileName, '.', '')
ENDIF
* Append DLL extension if not there
IF ATC('.', tcFileName) = 0
tcFileName = tcFileName + '.dll'
ENDIF
tcFileName = PROPER(tcFileName)
* See if file exists
IF !FILE(tcFileName)
MESSAGEBOX([File '] + tcFileName + ;
[' does not exist.], 48, MSGBOXTITLE)
RETURN
ENDIF
* Verify it is a DLL
IF ATC('.dll', tcFileName) = 0
MESSAGEBOX([File '] + tcFileName + ;
[' is not a dll.], 48, MSGBOXTITLE)
RETURN
ENDIF
lcFileContents = FILETOSTR(tcFileName)
DO CASE
CASE ATC('foxwt',lcFileContents) <> 0
lcType = 'Multi-threaded'
CASE ATC('foxwd',lcFileContents) <> 0
lcType = 'Single-threaded'
OTHERWISE
lcType = 'Non-FoxPro'
ENDCASE
MESSAGEBOX('File '+ tcFileName + ' is a '+ ;
lcType + ' dll.', 64, MSGBOXTITLE)
2. To test a specific file, run the following code from the Command window:
DO TestADLL.PRG with <path and filename>
3. To have the program prompt you for a file, run the following code from the
Command window:
DO TestADLL.PRG
Additional query words: KBDSE
======================================================================
Keywords : kbCOMt kbvfp600 kbVS600sp2 kbVS600sp3
Technology : kbVFPsearch kbAudDeveloper kbVFP600
Version : WINDOWS:6.0
Issue type : kbhowto
=============================================================================