Why does it result in GPF?

[Peter Redei]

I am trying the followings w/o success:

#COMPILE EXE
#INCLUDE "WIN32API.INC"
%FORMAT_MESSAGE_FROM_HMODULE = &H800
DECLARE FUNCTION InternetGetLastResponseInfo LIB "wininet.dll" ALIAS "InternetGetLastResponseInfoA" _
    (lpdwError AS DWORD, lpszErrorBuffer AS ASCIIZ, lpdwErrorBufferLength AS DWORD) AS INTEGER
DECLARE SUB ErrorOut(BYVAL dwError AS LONG, szFunc AS STRING)

GLOBAL szErrorMessage AS STRING
FUNCTION PBMAIN
    DIM szFunc AS STRING
    szFunc = "Whatever "
    Errorout 0, szFunc
END FUNCTION
SUB ErrorOut(BYVAL dwError AS LONG, szFunc AS STRING)
    DIM dwRet AS LONG
    DIM dwTemp AS DWORD PTR
    DIM szString1 AS ASCIIZ * 256
    DIM szString AS ASCIIZ * 2048
    DIM szFile AS ASCIIZ * 12
    DIM lp AS LONG
    szFile  = "wininet.dll"
    lp = GetModuleHandle(szFile)
    dwRet = FormatMessage(%FORMAT_MESSAGE_FROM_HMODULE, _
                      lp, dwError, 0, _
                      szString1, 256, 0)
    szErrorMessage = szFunc & " error code: " & FORMAT$(dwError) & " Message: " & szString1
    IF (dwError = 12003) THEN
        ' Extended error information was returned
        dwRet = InternetGetLastResponseInfo(dwTemp, szString, 2048)
        szErrorMessage = szString
    END IF
END SUB

This work fine in VB, but in PB it causes GPF at FormatMessage.
Any idea why?


Regards,


Peter Redei

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[Borje Hagsten]

don't know, but maybe the module handle? for ways to use formatmessage in
pb, see: http://www.powerbasic.com/support/pb...ad.php?t=22769

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[Trevor Lane]

According to Win32api.inc the szBuffer is an Asciiz and you are
passing a string. This will work in VB because VB has no native
support for ASCIIZ's In VB you pass a string ByVal.

Hope this helps
Trevor

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[Lance Edmonds]

Trevor, maybe I'm missing something, but which dynamic string is being passed to an API here? I only see ASCIIZ strings being passed to API functions.

The problem that I can see is that InternetGetLastResponseInfo() expects the buffer size to be specified in TCHARS (Unicode characters) which means that the value passed for the buffer size should be 0.5 * the buffer byte size count, less the null-terminator character (two bytes in unicode). See http://msdn.microsoft.com/library/de...sponseinfo.asp

Therefore, the call should look something like this:

dwRet = InternetGetLastResponseInfo(dwTemp, szString, [b](SIZEOF(szString) - 1) \ 2[/b])

Finally, the buffer content will probably need to be converted to ANSI...

------------------
Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Lance Edmonds]

One more thing: this API returns a BOOL, which should be translated to LONG in PowerBASIC, not INTEGER... therefore, the DECLARE statement is also incorrect.

------------------
Lance
PowerBASIC Support
mailto:[email protected][email protected]</A>

[Trevor Lane]

Oops,

Sorry, I am sure the first time I read the code szString1 was dimensioned as a string. Obviously not I probably saw szFunc.



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[Peter Redei]

Thank you for all replies.
The problem Lance, is not with InternetGetLastResponseInfo. The program never gets there. It is already blowing at FormatMessage.
I tried to use Semen's code following the link that Borje gave me and loading the library instead of GetModuleHandle, although the function I used returned a valid handle.
It did not change anything. GPF as usual...
Any other ideas?

Regards,

Peter Redei


------------------

[Peter Redei]

Never mind...
Changing as

dwRet = FormatMessage(%FORMAT_MESSAGE_FROM_HMODULE, _
BYVAL lp, dwError, BYVAL 0&, _
szString1, SIZEOF(szString1), BYVAL 0&)

works.

Thank you all.


Regards,

Peter Redei

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