COMException (ThrowExceptionForHR) => handle is invalid when calling Marshal.FreeHGlobal

Question

Hello

In my application, i read and write a lot from pointers (System.IntPtr). Somewhere at a "Marshal.FreeHGlobal()" (i've got a lot of them, and it varies where the program stops) i get this Exception:

"System.Runtime.InteropServices.COMException (0x80070006): The handle is invalid.
   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHR(Int32 errorCode, IntPtr errorInfo)
   at System.Runtime.InteropServices.Marshal.ThrowExceptionForHR(Int32 errorCode)
   at System.Runtime.InteropServices.Marshal.FreeHGlobal(IntPtr hglobal)
   at BTR2_DLL_Test.Form1.Button11_Click(Object sender, EventArgs e) in C:\DEV_OLD\VS2003\Testjes\BTR2_DLL_Test\BTR2_DLL_Test\Form1.vb:line 714"

A closer look gives me the TargetSite: ThrowExceptionForHR

Has anyone had a similar problem before? Should i provide more information?

Let me know.

Kind regards,
John

Answer 1

Assuming your FreeHGlobal() properly matches an AllocHGlobal() and you don't call it more than once: you've probably got stray pointers or are overrunning buffers and destroying the heap...

Answer 2

Problem solved. I indeed tried to free the pointer a second time in some cases.

Thx