Process Handle & Process ID, what is the difference?

[Cy_]

Hi,
What is the difference between the Process Handle & The Process ID?
Using Spy++ I can see the Process ID but, I cannot find the Process Handle?!

thanks

[wildfrog]

A process id identifies a process and is unique through out the system. A handle is unique within a single process.
So, if process A holds a handle to process T, and process B holds a handle to process T, then these two handle will/may be different.

To copy/move a handle from one process to another you can use DuplicateHandle (simply passing the handle value isn't enough).

- petter

[Cy_]

A process id identifies a process and is unique through out the system. A handle is unique within a single process.
So, if process A holds a handle to process T, and process B holds a handle to process T, then these two handle will/may be different.

To copy/move a handle from one process to another you can use DuplicateHandle (simply passing the handle value isn't enough).

- petter
Petter,
Thanks for the explanation, things are more clear now. However:
1- "Will/May" or MUST? can 2 Process Handles be the same within the same Process ID?
2- If everything has a HWND that identifies the process exclusively then why is a Process Handle necessary?
3- How can one see the Process Handle? like by Spy++ or is there a tool etc.?

thanks

Cy

[wildfrog]

1- "Will/May" or MUST? can 2 Process Handles be the same within the same Process ID?
One process can have multiple hadles to a process T, and all those handles will be different.


2- If everything has a HWND that identifies the process exclusively then why is a Process Handle necessary?
HWND is a handle to a window, not a process.

3- How can one see the Process Handle? like by Spy++ or is there a tool etc.?Well, there is no such thing as the process handle. There can be many handles to a single process. AFAIK www.sysinternals.com has such an utility.

- petter

[Cy_]

petter,
thanks for the useful link...:)

Cy