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]

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]

"Eric Kaplan" <to*********@yahoo.comwrote in message
news:ip********************************@4ax.com...

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]

On Apr 8, 7:48 pm, "Christopher Pisz" <[e-mail]:

"Eric Kaplan" <[e-mail] in message

news:ip********************************@4ax.com...

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]

On Apr 9, 6:58 am, Martin York <[e-mail]:

On Apr 8, 7:48 pm, "Christopher Pisz" <[e-mail]:

[...]

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:ja*********@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientierter Datenverarbeitung
9 place Sémard, 78210 St.-Cyr-l'École, France, [phone]

[Nick Keighley]

On 9 Apr, 10:05, James Kanze <[e-mail]:

On Apr 9, 6:58 am, Martin York <[e-mail]:

On Apr 8, 7:48 pm, "Christopher Pisz" <[e-mail]:

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."