CreateFile/CloseHandle increases win32 Handle Count

Thread View: borland.public.cppbuilder.nativeapi

2 messages

[T] Back to Threads [V] Tree View [G] Group Articles

2 total messages Started by Christian Lotze Thu, 05 Jun 2008 07:25

#308

Author: Christian Lotze
Date: Thu, 05 Jun 2008 07:25

27 lines
1725 bytes

Hi all,

I'm reading an external harddisk directly with:


   DeviceString = "\\\\.\\PHYSICALDRIVE"+IntToStr( HardDisk );
   hDevice = CreateFile( DeviceString.c_str(),
                         GENERIC_READ,
                         FILE_SHARE_READ | FILE_SHARE_WRITE,
                         NULL,
                         OPEN_EXISTING,
                         0,
                         0);

..... (SetFilePointer/ReadFile)

   CloseHandle(hDevice);

This increases count of win32 handles every time
  Createfile creates two handles
  CloseHandle closes only one of theses handles

(You can monitor this behaviour with processexplorer.)

Any hints?

Thanks, Christian

Re: CreateFile/CloseHandle increases win32 Handle Count

#311

Author: Bob Gonder
Date: Thu, 05 Jun 2008 14:27

47 lines
1979 bytes

Christian Lotze wrote:

>This increases count of win32 handles every time
>  Createfile creates two handles
>  CloseHandle closes only one of theses handles
>
>(You can monitor this behaviour with processexplorer.)
>Any hints?

You must be doing something else.
This app shows only one more handle after CreateFile.
And it goes away after DeleteHandle.
Do you have PE set to show all of the handle details?

#include	"windows.h"
#include	<conio.h>

void pause(void)
{	cputs( "\r\nCheck for number of handles, then press any key");
	getch();
}

int main(void)
{	HANDLE		h;
	DWORD		written;
	char		str[1024];

	pause();
	h = CreateFile( "\\\\.\\PHYSICALDRIVE0",
                         GENERIC_READ,
                         FILE_SHARE_READ | FILE_SHARE_WRITE,
                         NULL,
                         OPEN_EXISTING,
                         0,
                         0);
	if(INVALID_HANDLE_VALUE!=h)
	{
		pause();
		SetFilePointer(h,0,NULL,FILE_BEGIN);
		pause();
		ReadFile(h,str,sizeof(str), &written,0);
		pause();
		CloseHandle(h);
		pause();
	};
	return 0;
}

Thread Navigation

This is a paginated view of messages in the thread with full content displayed inline.

Messages are displayed in chronological order, with the original post highlighted in green.

Use pagination controls to navigate through all messages in large threads.

Back to All Threads