如何在C中生成一个GUID？(How to generate a GUID in C?)

如何在C中生成一个GUID？(How to generate a GUID in C?)

我想要生成guid来插入到SQLite数据库（即不支持db本身）。 但是，我想控制某些属性：

生成增加的guid值的有序性。 计算机独立。 数据库是公开的，可能/可能不希望GUID允许某人将数据追溯回特定机器。 '足够'的随机性。 guid是db中的关键，它将与许多其他dbs合并，并且可能会变得非常大，这意味着像许多算法那样伪造guid是没有用的。 我可以处理使用特定于系统的API，但请链接Windows和Linux函数，并且像SQLite之类的东西是首选的，我可以使用其他人编写的代码。 我还希望可以在商业应用程序中使用的代码。

I want to generate guids to insert into a SQLite database ( no support from the db itself). However, I would like to have control over certain properties:

Orderedness for generating increasing guid values. Computer independence. The db is public and may/may not want guids to allow someone to trace data back to a specific machine. 'Enough' randomness. The guids are keys in the db which is going to be merged with a lot of other dbs and can get quite large, meaning that faking a guid like many algorithms do is no good. I can deal with using system specific APIs but please link both Windows and Linux functi, and something like SQLite is preferred, where I can just use code someone else wrote. I would also prefer code which is OK to use in a commercial application.

最满意答案

您可以使用或查看Boost.Uuid的代码：

http://www./doc/libs/1_47_0/libs/uuid/index.html

它是一个C ++库，但仍然可以在代码作者的内部到如何在多个系统上检索Uuid。 上次我检查（2010年1月），我发现至少以下Windows和Linux / Solaris的实现（此信息可能已过时）：

Linux / Solaris上的UUID / GUID

打开文件到/dev/urandom并读取足够的字节（16）以组成GUID / UUID。

Windows上的UUID / GUID

使用以下WinAPI函数

CryptAcquireContext获取随机上下文 CryptReleaseContext释放获取的随机上下文 CryptGenRandom生成足够的字节来组成一个GUID / UUID

其他实现

在GUID / UUID上的页面有一个您可以使用/学习的替代实施列表：

https://en./wiki/UUID#Implementati

关于你的条件

有一个GUID / UUID类型始终是随机的（ 版本4 ），这意味着要与其他GUID / UUID语义兼容，您应该尊重它。

现在，您需要及时订购GUID / UUID。 在不削弱GUID / UUID随机性的情况下，唯一的方法就是将16字节的GUID / UUID作为无符号整数的前缀（这将使您的标识符数据为20字节或更多，具体取决于您的整数）。 只需生成一个GUID / UUID，然后增加整数。

You can either use or look at the code of Boost.Uuid :

http://www./doc/libs/1_47_0/libs/uuid/index.html

It is a C++ library, but still, you can find inside how the code author retrieved the Uuid on multiple systems. Last time I checked (january 2010), I found at least the following implementati for Windows and Linux/Solaris (this info could be outdated):

UUID/GUID on Linux/Solaris

Open a file to /dev/urandom and read enough bytes (16) to make up a GUID/UUID.

UUID/GUID on Windows

Use the following WinAPI functi

CryptAcquireContext to acquire a random context CryptReleaseContext to release the acquired random context CryptGenRandom to generate enough bytes to make up a GUID/UUID

Other implementati

The Wikipedia page on GUID/UUID has a list of alternative implementati you could use/study:

https://en./wiki/UUID#Implementati

About your conditi

There is a GUID/UUID type which is always random (the version 4), meaning that to be compatible with other GUID/UUID semantics, you should respect that.

ow, you want the GUID/UUID to be ordered in time. The only way to do that without weakening the GUID/UUID randomness would be to prefix the 16-byte GUID/UUID with an unsigned integer (which would make your identifier data 20-bytes, or more, depending on your integer). Just generate a GUID/UUID, and increase the integer.