asked on

getwindowsdirectory (netdll.dll???)

Hi

I use the function GetWindowsDirectory, I have no problem in win95 but in winnt 4, when the function is
executed, its give me an error :

var directory : string;
GetWindowsDirectory(PChar(directory),Max_Path);

"""An exception as occurs (EAccessViolation) with the message access violation of address '77F66DEF'
of module 'netdll.dll'. Write of address '00403DD5'.Processus stop """

P.S.:(i translate from the french error)

I dont understand what going on.

Thanks

rene_moeller

Hi sierra20,

I get the same error in NT, but this piece of code works:

var
Buffer : PChar;
BufferSize : integer;
begin
BufferSize := 255;
GetMem(Buffer, BufferSize);
GetWindowsDirectory(Buffer, BufferSize);
ShowMessage(StrPas(Buffer));
FreeMem(Buffer);
end;

Rene_Moeller

khenr29j

You need to allocate memory for the string before you let Windows overwrite it. NT is probably more sensitive to memory overwrites and doesn't let you shoot yourself in the foot like Windows '95 does.

Corrected code:
var directory : string;
Begin
SetLength(Directory, GetWindowsDirectory(Nil, 0)+1);
GetWindowsDirectory(PChar(directory),Max_Path);
// etc

The first line allocates enough memory to hold the length of the windows directory returned by GetWindowsDirectory(Nil, 0) and adds one character to hold the trailing null character.
Best wishes,
-Kristoffer

erajoj

Hi,
In Windows 95, everything seems to be allowed!? ;-)
You have to allocate heap space by setting the string length to MAX_PATH:

var directory : string; // creates empty string

SetLength( directory, MAX_PATH ); // allocates heap space
GetWindowsDirectory(PChar(directory),MAX_PATH); // now working!

/// John

erajoj

Sorry!
I was too slow...

/// John

sierra20

ASKER

Hi

Kristoffer, you can answers the question because you give me the best answers.

Thanks.

Sierra

ASKER CERTIFIED SOLUTION

khenr29j

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