.NET : How to PInvoke UpdateProcThreadAttribute
Question
I am trying to PInvoke UpdateProcThreadAttribute()
on Windows 7 but my attempts just keep returning FALSE with a Last Win32 Error of 50.
Function declaration (from MSDN)
BOOL WINAPI UpdateProcThreadAttribute(
__inout LPPROC_THREAD_ATTRIBUTE_LIST lpAttributeList,
__in DWORD dwFlags,
__in DWORD_PTR Attribute,
__in PVOID lpValue,
__in SIZE_T cbSize,
__out_opt PVOID lpPreviousValue,
__in_opt PSIZE_T lpReturnSize
);
Here is my attempt at the PInvoke signature:
[DllImport("kernel32.dll", CallingConvention = CallingConvention.Winapi, SetLastError = true)]
public static extern bool UpdateProcThreadAttribute
(
IntPtr lpAttributeList,
UInt32 dwFlags,
ref UInt32 Attribute,
ref IntPtr lpValue,
ref IntPtr cbSize,
IntPtr lpPreviousValue,
IntPtr lpReturnSize
);
Is this declaration sensible? Thanks.
Solution
You have a few problems with your declaration but the one that is giving you the not supported error is the Attribute parameter. A DWORD_PTR is not a pointer but rather a pointer sized unsigned integer so rather than ref uint it should be an IntPtr.
The declaration I would use is:
[DllImport("kernel32.dll", SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
private static extern bool UpdateProcThreadAttribute(
IntPtr lpAttributeList, uint dwFlags, IntPtr Attribute,
IntPtr lpValue, IntPtr cbSize, IntPtr lpPreviousValue,
IntPtr lpReturnSize);
EDIT:
I tried to do this as a comment but it doesn't take to code very well.
For a process handle you need an IntPtr to hold the handle. So you would need something like:
IntPtr hProcess //previously retrieved.
IntPtr lpAttributeList //previously allocated using InitializeProcThreadAttributeList and Marshal.AllocHGlobal.
const int PROC_THREAD_ATTRIBUTE_PARENT_PROCESS = 0x00020000;
IntPtr lpValue = Marshal.AllocHGlobal(IntPtr.Size);
Marshal.WriteIntPtr(lpValue, hProcess);
if(UpdateProcThreadAttribute(lpAttributeList, 0, (IntPtr)PROC_THREAD_ATTRIBUTE_PARENT_PROCESS, lpValue, (IntPtr)IntPtr.Size, IntPtr.Zero, IntPtr.Zero))
{
//do something
}
//Free lpValue only after the lpAttributeList is deleted.
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