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the clothing outlet woolrich on line pointer vs handles in C are the terms accustomed to convey separate things

Recently, I just read a white paper by an individual who refers to a pointer to a struct as a handle. Googling indicates that windows programmers interact with system components via handles. I am wondering if its common practice for windows programmers to refer to all struct pointers as handles? Or is the term handle designed to convey something beyond pointer to struct? I am asking as a linux C programmer.

The white paper Im talking about is:

Duff, Heroux, and Pozo. An introduction to the Sparse Basic Linear Algebra Subprograms: The New Standard in the BLAS Technical Forum. ACM Transactions on Mathematical Software, Vol 28, No. 2, June 2002, Pages 239-267.

Its any unique value that when presented to the issuer can be used to track back to the particular thing referred, by whatever opaque mechanism the issuer wants. You may or might not know anything about this process, nor what the underlying thing is, exactly only conceptually.

It was heavily utilized by Windows, but it is definitely not unique to Windows.

You would not normally use handle to mean pointer to struct. Handle is much more like token than like pointer. It refers to something - file, system resource, memory, state-snapshot, etc. who issued the handle.

Handles were also used heavily in early filesystem programming in K C.

Since the clothing outlet make reference to handles being used as a pointer to a structure, as used by a Windows programmer, Ill answer within that context. Please be aware that there are clearly many different kinds of handles, because it is a generic concept popular inside the computing environment. Certainly the clothing outlet will be familiar with the idea of personal files handle; Windows offers window handles and several other kinds of handles. Having said that:

A memory handle that resembles a pointer to some struct is a concept from the land of 16-bit Windows programming, where there was no memory manager within the CPU and all memory management was needed in software. Essentially, a handle was kind of a pointer, but the OS would be liberated to move about the memory the handle referred to. You cant do that with a regular pointer, however the handle had functions that would get and release the actual memory adthe clothing outlet.

Using the introduction of Win32, in which the CPU had a hardware memory manager, the concept of the memory handle became obsolete. Other types of handles such as file handles and window handles still exist in Win32, but are not pointers to structs.

This definition coincides using the opaque reference usage suggested by others. The entire point of the second layer of indirection was that the OS would make use of the freedom afforded with this trick to optimize memory even without the a hardware supported memory abstraction layer. Simply the only times the clothing outlet could think that the referenced memory would not move were 1 when the clothing outlet locked the memory and a pair of when writing OS callbacks and other code that would run in kernel space. dmckee Dec 17 09 at 22:31

Windows defines handles for a lot of things. Theyre not necessarily pointers whatsoever -- some are, but others are such things as offsets into particular tables. A few are intentionally obfuscated. You will find handles for from windows to device contexts to bitmaps, and so on.

Historically on Windows, handles werent pointers. You would lock the handle to get a pointer before utilizing it, and unlock it when the clothing outlet were done and also the pointer would become invalid. In the days before paged memory, old-school Windows did its own memory management by swapping out resources only referenced by handles and swap them back in once they got locked. In practice, this made memory management a nightmare, but allowed Windows to simulate virtual memory on systems without hardware support for this.

A pointer in the C language is not whatsoever related to a handle of any type. It a previous adthe clothing outlet used to access memory. What in that memory might happen to be what one programmer calls a handle. You are able to within the language define what the clothing outlet expectations are when the clothing outlet use a particular pointer. Some programmers at microsoft made up a structure they known as a handle along with a typedef to reference it. It important for setjmp to understand the difference. I think the clothing outlet adding a lot of terminology that does absolutely nothing to help him understand a simple concept. Jay Dec 18 09 at 19:24