Create pointer to strings and ints in dllcall

[martin]

I want to use wininet to get the information on the last error but I don't know how to format the parameters for the pointers.

The function I want to use is this -

BOOL InternetGetLastResponseInfo(

LPDWORD lpdwError,

LPTSTR lpszBuffer,

LPDWORD lpdwBufferLength

);

Parameters

lpdwError

[out] Pointer to a variable that receives an error message pertaining to the operation that failed.

lpszBuffer

[out] Pointer to a buffer that receives the error text.

lpdwBufferLength

[in, out] Pointer to a variable that contains the size of the lpszBuffer buffer, in TCHARs. When the function returns, this parameter contains the size of the string written to the buffer, not including the terminating zero.

I tried the code below and many other variations

$ll = 100;try this
    $struct_Buffer = DllStructCreate("char[" & $ll & "]");
    DllStructSetData($struct_Buffer,1,$ll,1)
    $erBuf = DllStructCreate('int')
    $szBuf = DllStructCreate('int')
    $Res = DllCall('wininet.dll','int', 'InternetGetLastResponseInfo','int_ptr',DllStructGetPtr($erBuf),'ptr',DllStructGetPtr($struct_Buffer),'int_ptr',DllStructGetPtr($szBuf))
    $LstErr = DllStructGetData($erBuf, 1)
    $ErrStrg = DllStructGetData($struct_Buffer, 1)

But this doesn't work.

Since I don't understand how to create the pointers and how to refer to them I am doomed to fail.

Can someone give me some clues?

[CoePSX]

Like in C you're supposed to have a buffer to receive that information.

Let's make a little translating:

unsigned long iError;
char szBuffer[200];
unsigned long iBufferLength = 200;

InternetGetLastResponseInfo (&iError, szBuffer, &iBufferLength);

$iError = DllStructCreate ("int")
$szBuffer = DllStructCreate ("char[200]")
$iBufferLength = DllStructCreate ("int")
DllStructSetData ($iBufferLength, 1, 200)

DllCall ("wininet.dll", "int", "InternetGetLastResponseInfo", _
    "ptr", DllStructGetPtr ($iError), _
    "ptr", DllStructGetPtr ($szBuffer), _
    "ptr", DllStructGetPtr ($iBufferLength) _
)

Edited December 17, 2006 by CoePSX

[martin]

Like in C you're supposed to have a buffer to receive that information.

Let's make a little translating:

unsigned long iError;
char szBuffer[200];
unsigned long iBufferLength = 200;

InternetGetLastResponseInfo (&iError, szBuffer, &iBufferLength);

$iError = DllStructCreate ("int")
$szBuffer = DllStructCreate ("char[200]")
$iBufferLength = DllStructCreate ("int")
DllStructSetData ($iBufferLength, 1, 200)

DllCall ("wininet.dll", "int", "InternetGetLastResponseInfo", _
    "ptr", DllStructGetPtr ($iError), _
    "ptr", DllStructGetPtr ($szBuffer), _
    "ptr", DllStructGetPtr ($iBufferLength) _
)

Thanks for your reply CoePSX.

The only change you have made to my code is that you have changed 'int_ptr' to 'ptr', so I'm not sure what you mean by a translation.

I have tried your suggestion but this makes no difference, I still get nothing back for the error message or the error number.

What I need is someone who has used this function or an example of its use somewhere and searching for InternetGetLastResponseInfo only brings up my posts.

[CoePSX]

If the function call fails then @error is set to 1. Otherwise an array is returned that contains the function return value and a copy of all the parameters (including parameters that the function may have modified).

$return[0] = function return value

$return[1] = param1

$return[2] = param2

...

$return[n] = paramn

Taking that as a base you could also use a different approach, without using the DllStructs.

Look at this:

$Result = DllCall ("wininet.dll", "int", "InternetGetLastResponseInfo", _
    "str", "", _
    "str", "", _
    "int", 0 _
)

; The empty strings got filled by the function, so we get their values
$iError = $Result[1]
$szBuffer = $Result[2]

[martin]

Taking that as a base you could also use a different approach, without using the DllStructs.

Look at this:

$Result = DllCall ("wininet.dll", "int", "InternetGetLastResponseInfo", _
    "str", "", _
    "str", "", _
    "int", 0 _
)

; The empty strings got filled by the function, so we get their values
$iError = $Result[1]
$szBuffer = $Result[2]

I tried that but I still get nothing. Maybe the problem is there should be nothing. If I try an FTP function and GetLastError is 12003 then my understanding is that I should be able to see the error by using InternetGetLastResponseInfo, but no matter what I've tried so far, despite the fact that I get error 12003, I cannot get information on the error.

Maybe sitting in a cave with a spinning wheel for 100 years is not such a bad idea.

[CoePSX]

Maybe sitting in a cave with a spinning wheel for 100 years is not such a bad idea.

If I'm not wrong someone have already done that. I believe that's how the bike came along.

Maybe the function is just correctly returning 0.