向下兼容ABI使用升压创建库 [英] Creating Library with backward compatible ABI that uses Boost

问题描述

我的工作有一定的C ++库（或更多框架）。我想使它落后
以previous版本preserving兼容，不仅API兼容性也ABI（如伟大的工作，Qt的一样）。

I'm working on a certain C++ library (or more framework). I want to make it backward compatible with previous versions preserving not only API compatibility but also ABI (like the great job Qt does).

我使用大量的Boost功能，似乎对我来说这使得向后兼容性只是不可能的，除非我强迫用户具有完全相同的（有时旧）加速版本。

I use lots of functionality of Boost and it seems for me that this makes backward compatibility just impossible, unless I force a user to have exactly the same (sometimes old) version of Boost.

有什么办法（无需重写升压的1/2），使一些preFIX围绕其命名空间/从加速的用户版本的干扰，以便其重命名为prevent呢？

Is there any way (without rewriting 1/2 of Boost) to make some "prefix" around its namespace/rename it in order to prevent it from interfering with a user version of Boost?

例如我libXYZ使用升压1.33，它具有类的boost :: foo的。在版本1.35 的boost :: foo的进行了升级，并加入新的成员，因此，的boost :: foo的从1.33 1.35是
ABI不兼容。因此，libXYZ的用户必须使用升压1.33或重新编译libXYZ与
升压1.35（即可能已经打破的方式XYZ不会编译一些API）。

For example my libXYZ uses Boost 1.33 and it has class boost::foo. In version 1.35 boost::foo was upgraded and new member was added, so, boost::foo from 1.33 and 1.35 are not ABI compatible. So, a user of libXYZ must use Boost 1.33 or recompile libXYZ with Boost 1.35 (that may be already had broken some API in a way XYZ would not compile).

注意：我说的是UNIX / Linux操作系统与ELF其中，动态链接类似于静态链接，所以你不能用两个不同版本的库链接，因为符号会干扰

Note: I'm talking about UNIX/Linux OS with ELF where dynamic linking is similar to static linking, so you can't link with two different versions of libraries because symbols would interfere.

一个合适的解决方案，我可以想到的是把加速在其他一些私人空间。因此，libXYZ会使用 :: XYZ ::提高:: foo的而不是的::提高:: foo的。这将prevent碰撞升压用户可以使用其他版本。

One suitable solution I may think of is putting Boost in some other private namespace. So, libXYZ would use ::XYZ::boost::foo instead of ::boost::foo. This would prevent collision with other version of Boost that user may use.

因此​​，libXYZ将继续与升压1.33静态或动态与它withing其他的命名空间，假设，它链接到工作：

So, the libXYZ would continue to work with Boost 1.33 statically or dynamically linked with it withing other namespace, assuming, that it:

• 会不会暴露加速API之外。


• 将保持公开的API的稳定的专用版本。

有没有办法做这样的事情升压？

Is there any way to do such things with Boost?

编辑：最后，我决定创建一个脚本，将在源头上一些自定义符号重命名所有升压符号

Finally I decided to create a script that would rename all boost symbols in the source to some custom symbol.

理由：构建过程的简化，独立的编译器知名度的支持，另外，它的知名度适用于动态库只，静态这也不行，所以我需要单独建立和依赖关系为每种类型的库

Rationale: simplification of build process, independent of compiler visibility support, also, it visibility works on dynamic libraries only, for static this does not work, so I need separate builds and dependencies for each type of libraries.

脚本可有： HTTP：//art-blog.no- ip.info/files/rename.py

编辑2：最新升压BCP版本支持重命名空间

Edit 2: Latest version of Boost BCP supports namespace renaming.

推荐答案

基本上，只要确保的公共接口库中不公开提振。您可以随时使用它不过多你想要的内部。通常，具有一个库的接口取决于另一个库是坏的（除非它取决于像STL一个标准库）。升压几乎适合标准库类，但它的变化ABI这么多，你的接口应不会使用它。

Basically, just make sure the public interface to your library does not expose Boost. You can always use it however much you want internally. Generally, having the interface of a library depend on another library is bad (unless it depends on a standard library like STL). Boost almost fits into the "standard" library category, but its ABI changes so much that that your interface shouldn't use it.

要确保你没有揭露升压符号，有一些事情可以做：

To make sure you don't expose the Boost symbols, there are a few things you could do:

一个。与 -fvisibility隐藏= 编译和标记与所有公共符号__属性__（（能见度（默认）））。您可以使用宏来简化这一过程：

A. compile with -fvisibility=hidden and mark all public symbols with __attribute__((visibility("default"))). you could use a macro to make this easier:

#define ABI __attribute__((visibility("default")))

乙。做这样的事情：

#pragma GCC visibility push(hidden)
#include <boost/whatever.hpp>
#pragma GCC visibility pop

您也应该把这个包周围，你不想出口，或声明这个__属性__所有其他内部符号（（能见度（隐藏）））。同样，你可以使用宏来简化这一过程：

You should also wrap this around all other internal symbols that you don't want exported, or declare this with __attribute__((visibility("hidden"))). Again, you could use a macro to make this easier:

#define INTERNAL __attribute__((visibility("hidden")))

在这些选项中，我喜欢一个更好的，因为它使你明确地想想哪些符号出口，所以你不小心导出你不想要的东西。

Of these options, I like A better, because it makes you explicitly think about which symbols are exported, so you don't accidentally export things you don't want.

顺便说一句，你可以找到关于乌尔里希Drepper的制作的DSO如何写更多的信息共享库。

By the way, you can find a lot more information about making DSOs in Ulrich Drepper's How to Write Shared Libraries.

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