blocks|key|1164257|text|术语句柄通常指的是某个不透明的值，它只对生成它的API有意义。在Win32中，句柄类型要么是内核内存中的指针(应用程序无论如何都不能访问)，要么是某个内核内部数组的索引。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1164258|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

The term handle generally means some opaque value that has meaning only to the API which produced it. In Win32, the HANDLE type is either a pointer in kernel memory (which applications cannot access anyway) or an index into some kernel-internal array.

blocks|key|1379215|text|我使用句柄这个词来表示指向表示资源的“对象”的指针--通常是操作系统资源，而指针只是指向一些内存。如果你有一个句柄，你不应该尝试直接读写字节，而是通过提供的方法来操作它。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1379216|句柄通常被实现为不透明的void+*，这进一步鼓励您不要尝试直接取消对它的引用。|offset|length|style|CODE|1379217|entityMap^0|0|C|6|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|I|$]]

I use the word handle to mean a pointer that points to an "object" that represents a resource - often an OS resource, whereas a pointer just points to some memory. If you have a handle to something, you shouldn't try to read and write bytes into it directly, but manipulate it through provided methods.

Often handles are implemented as an opaque <code>void *</code>, which is further encouragement not to try to directly dereference it.

blocks|key|1379315|text|术语句柄用于表示允许您访问另一个对象的任何技术。句柄可以是指针、引用、指向指针的指针等。但可以肯定的是，它与类、对象等相关。因此句柄不需要总是指向结构的指针。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1379316|-AD。|1379317|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

The term handle is used to mean any technique that lets you access to another object. A handle can be a pointer, a reference, a pointer to a pointer, etc.. But sure its related to classes, objects etc. So handle need not always be a pointer to structure. 

-AD.

blocks|key|1164557|text|“句柄”这个术语并不是起源于Windows，尽管它在Windows程序员中已经很普遍了。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1164558|在C标准库(stdio.h)中，文件句柄是指向C库使用的数据结构的指针。|1164559|纯Unix编程使用文件描述符，它是内核数据结构的索引，但指针在Unix中用作句柄已有30多年的历史。|1164560|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

The term "handle" didn't orignate on Windows, though it became widespread among Windows programmers.

In the C standard library (stdio.h), file handles are pointers to a data structure used by the C library.

Pure Unix programming uses file descriptors, which are indexes into a kernel data structure, but pointers have been used as handles in Unix for over 30 years.

blocks|key|1164617|text|“句柄”是一个逻辑术语，而不是一个物理术语。它是物理对象的代理，代码对该对象有更深入的了解。指向结构的指针就是这样一种代理，但还有许多其他的可能性。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1164618|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

"Handle" is a logical term, not a physical one. It's meant as a proxy to a physical object to code that has more intimate knowledge of the object. A pointer to a struct is one such proxy, but there are many other possibilites.

blocks|key|1164315|text|不，在Windows程序员中，将指针引用为句柄并不是特别常见，但这样做也没有错。术语“句柄”通常用来描述你用来访问的东西，从这个意义上说，它都是指针句柄(但并不是所有的句柄都是指针)。Win32的句柄是AFAIK，通常不是指针，而是指向内部OS表的索引-但这可能会在未来的Windows版本中发生变化。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1164316|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

No, it is not particularly common amongst Windows programmers to refer to pointers as handles, but doing so isn't WRONG either. The term "handle" is usually used to describe something you use to access something through, and in that sense are all pointers handles (but not all handles are pointers). Win32's handles are AFAIK usually not pointers, but instead indices to internal OS tables - but this might change in future versions of Windows.

blocks|key|1164476|text|在MacOS编程的旧时代，回到OSX之前，句柄是指向指针的指针。这使得操作系统可以在不使用户指针失效的情况下移动东西。当我们可以假设指向的对象不会移动时，有一些规则，我不记得了。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1164477|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

In the old days of MacOS programming, back before OSX, a handle was a pointer to a pointer. That allowed the OS to move things around without invalidating the user's pointers. There were rules on when we could assume the pointed-to object wouldn't move, which I don't remember.

blocks|key|1164399|text|句柄通常是不需要直接引用的指针。相反，您将它们传递给API调用，API调用在底层结构上进行操作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1164400|在过去的Windows中，句柄不是指针。您可以在使用句柄之前锁定句柄以获取指针，并在使用完毕后将其解锁(并且指针将变为无效)。在分页内存之前的日子里，老式的Windows通过交换出仅由句柄引用的资源，并在它们被锁定时将它们换回，从而实现了它自己的内存管理。在实践中，这使得内存管理成为一场噩梦，但允许Windows在没有硬件支持的系统上模拟虚拟内存。|1164401|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

Handles are generally pointers that you don't directly need to dereference. Rather you pass them to API calls which operate on the underlying structs.

Historically on Windows, handles were not pointers. You would lock the handle to get a pointer before using it, and unlock it when you were done (and the pointer would become invalid). In the days before paged memory, old-school Windows did it's own memory management by swapping out resources only referenced by handles and swap them back in when they got locked. In practice, this made memory management a nightmare, but allowed Windows to simulate virtual memory on systems without hardware support for it.

blocks|key|1379749|text|我可能比大多数受访者年龄都大，因为我在早期(80年代末)的Macintosh和16位和32位Windows上都靠C编程为生。在那些古老的时代(当IBM大型机可能只有256k内存时)，句柄始终是指向内存指针的指针(或表偏移量)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1379750|正如前面提到的，这允许指向内存块的指针表由操作系统管理，而不会使程序员使用的“句柄”无效。不幸的是，我不记得我们是如何保证在使用句柄时分配的块不会被移动的。|1379751|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

I'm probably older than most of the respondents, having earned a living coding in C on both the early (late 80s) Macintosh and both 16 and 32-bit Windows. In those ancient times (when an IBM mainframe might have only 256k of memory) a handle was always a pointer (or table offset) to a memory pointer.

As a previous respondent mentioned, that allowed tables of pointers to memory blocks to be managed by the OS without invalidating the "handles" used by the programmer. Unfortunately, I do not remember how we guaranteed that an allocated block would not be moved while we using the handle.

blocks|key|1379802|text|实际上，指针是一个变量，它包含另一个变量的地址，而句柄是一个指向指针的指针，即包含另一个指针地址的指针。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1379803|int+x=10;

int+*a=&x;//+this+is+a+simple+pointer

int+*b=a;//+this+is+a+handle|code-block|syntax|javascript|1379804|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Actually a pointer is a variable which contains the address of another variable,but a handle is a pointer to a pointer i.e a pointer which contains the address of another pointer
FOR EX:

<pre><code>int x=10;

int *a=&amp;x;// this is a simple pointer

int *b=a;// this is a handle
</code></pre>

blocks|key|1164229|text|指针绝对不同于句柄。指针是内存中未指定内容的地址。指向结构的指针可以称为“句柄”(通常使用“typedef”)。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1164230|句柄是在编写windows操作系统时使用的概念。指针是C语言的一部分。|1164231|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

A pointer is definitely different than a handle. A pointer is an address of something unspecified in memory. A pointer to a structure can be called a "handle" (usually by using 'typedef').

A handle is a concept used in writing the windows operating system.
A pointer is a part of the C language.

Recently, I read a white paper by an individual who refers to a pointer to a struct as a handle. The author was clearly someone who had written C code on the windows platform previously. Googling indicates that windows programmers interact with system components via handles. I am wondering if it is common practice for windows programmers to refer to all struct pointers as handles? Or is the term handle meant to convey something beyond pointer to struct? I am asking as a linux C programmer.

The white paper I am referring to is:
Duff, Heroux, and Pozo. An Overview of the Sparse Basic Linear Algebra Subprograms: The New Standard from the BLAS Technical Forum. ACM Transactions on Mathematical Software, Vol 28, No. 2, June 2002, Pages 239-267.

pointer vs handles in C (are the terms used to convey separate things?)

数据结构

内存管理

Windows

MacOS

Unix

最近，我读了一个人写的白皮书，他把指向结构的指针作为句柄。作者显然是以前在windows平台上编写过C代码的人。Googling表明windows程序员通过句柄与系统组件交互。我想知道windows程序员把所有的结构指针都当作句柄来引用是不是很普遍？或者句柄这个术语的含义不仅仅是指向结构的指针？我是以linux C程序员的身份问的。我所指的白皮书是: Duff，Heroux和Pozo。稀疏基本线性

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