HANDLE

[Eric Kaplan]

In C++, there is datatype HANDLE
void* HANDLE

then HANDLE is similar to "file handle"?

which is unique identifier for a file, for a process, for a thread ...
etc

which is returned by a function when it's creating something - like
creating a thread, creating a process, creating a file ... etc

[Ian Collins]

Re: HANDLE

Eric Kaplan wrote:

In C++, there is datatype HANDLE
void* HANDLE
>
then HANDLE is similar to "file handle"?
>
which is unique identifier for a file, for a process, for a thread ...
etc
>
which is returned by a function when it's creating something - like
creating a thread, creating a process, creating a file ... etc
>

In standard C++ terms, it's probably just used as an opaque, unique
identifier. You would get more input on a windows programming group.

--
Ian Collins.

[Christopher Pisz]

Re: HANDLE


"Eric Kaplan" <tobycraftse@ya hoo.comwrote in message
news:ip2ov3ljpr 51sr00h29lo79od v5jtf5u0n@4ax.c om...

In C++, there is datatype HANDLE

Funny, it doesn't show up in any of my books as a primitive type.
I think you mean, "In the Windows SDK there is a data type HANDLE"

void* HANDLE
>
then HANDLE is similar to "file handle"?

Why not look it up in the MSDN?

[Martin York]

Re: HANDLE

On Apr 8, 7:48 pm, "Christophe r Pisz" <some...@somewh ere.netwrote:

"Eric Kaplan" <tobycraf...@ya hoo.comwrote in message
>
news:ip2ov3ljpr 51sr00h29lo79od v5jtf5u0n@4ax.c om...
>

In C++, there is datatype HANDLE

>
Funny, it doesn't show up in any of my books as a primitive type.
I think you mean, "In the Windows SDK there is a data type HANDLE"
>

void* HANDLE

>

then HANDLE is similar to "file handle"?

>
Why not look it up in the MSDN?

In computer science terms a 'handle' is a pointer to a pointer to a
resource.
The concept was used by many OS to allow the easy movements of
resources in memory.

But this is not specifically a C++ concept and you would need to look
up a comp-sci book to get full details.

[James Kanze]

Re: HANDLE

On Apr 9, 6:58 am, Martin York <Martin.YorkAma ...@gmail.comwr ote:

On Apr 8, 7:48 pm, "Christophe r Pisz" <some...@somewh ere.netwrote:

[...]

In computer science terms a 'handle' is a pointer to a pointer to a
resource.
The concept was used by many OS to allow the easy movements of
resources in memory.

Do you have a reference for that? I've always understood a
handle to be an opaque data type, used by some service providers
as an identifier of something. It could be a pointer to a
pointer, a simple pointer, an int, or even a string: just about
anything else the service provider wants to use. The critical
point was always that the type and semantics were opaque to the
client.

--
James Kanze (GABI Software) email:james.kan ze@gmail.com
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[Nick Keighley]

[OT] what's a handle? [Was: HANDLE]

On 9 Apr, 10:05, James Kanze <james.ka...@gm ail.comwrote:

On Apr 9, 6:58 am, Martin York <Martin.YorkAma ...@gmail.comwr ote:

On Apr 8, 7:48 pm, "Christophe r Pisz" <some...@somewh ere.netwrote:

In computer science terms a 'handle' is a pointer to a pointer to a
resource.
The concept was used by many OS to allow the easy movements of
resources in memory.

>
Do you have a reference for that?  

the MAC used to do this. I'm not sure it's particularly
widely used.

I've always understood a
handle to be an opaque data type, used by some service providers
as an identifier of something.  It could be a pointer to a
pointer, a simple pointer, an int, or even a string: just about
anything else the service provider wants to use.  The critical
point was always that the type and semantics were opaque to the
client.

on Unix it was common for a handle to be a small integer.
Think file handles.

C's FILE* is very handle like



--
Nick Keighley

"One of the main causes of the fall of the Roman Empire was that,
lacking zero, they had no way to indicate successful termination of
their C programs."