How to read a ptr to a string (returned by WM_Settingchange

[DieterMoeyersoon]

Hello all,

in my program I would like to respond to the WM_Settingchange, so I use

GUIRegisterMsg($WM_SETTINGCHANGE , "WM_SETTINGCHANGE")

The lParam parameter is a pointer to a string (see http://msdn.microsoft.com/en-gb/library/windows/desktop/ms725497(v=vs.85).aspx). How can I read this string from memory?

I've tried already with DLLStruct, but this doesn't seem to work well (I also don't know the length of the string). In another topic I found a reference to using __SQLite_szStringRead from SQLite.au3 but this doesn't work either. Any help is welcome.

Func WM_SETTINGCHANGE($hWnd, $iMsg, $wParam, $lParam)
#forceref $hWnd, $iMsg,$wParam
;$myString = __SQLite_szStringRead($lParam)
;$lParamString = DllStructCreate("char[128]", $lParam)
;$myString = DllStructGetData ($lParamString,1)
ConsoleWrite($myString & @cr)
EndFunc

Brgds

Dieter

[Andreik]

Have you read this note?

Note that some applications send this message with lParam set to NULL.

So it's not necessarily to have a pointer to a string.

[DieterMoeyersoon]

Hi Andreik,

yes I've seen that but I know for sure in certain cases (eg Group Policy updates) it should be a pointer to a string (eg "Policy")...

[trancexx]

So, what exactly is the problem, if there is any anymore?

First you check if lParam is not 0, then you use e.g. _WinApi_StringLen on that pointer to size the struct made at lParam address and then just read the content. How hard is that?

Edited December 13, 2012 by trancexx

[DieterMoeyersoon]

Hi trancexx,

this was indeed the function I was looking for.

Thanks for your help!