如何在C ++链接器知道的.lib包含哪些功能？ [英] How does the C++ linker know which .lib contains which functions?

问题描述

例如在加速。我设置的包括的目录MSVC ++ 2010的升压根目录，并有一个的#include＆LT;升压/ regex.hpp＆gt;在我的来源$ C ​​$ C。我设置的库的目录升压\\阶段\\ lib中但也有数百个文件，在那里 - 几个每个Boost库和这些升压： ：正则表达式：

For example in Boost. I set an include directory in MSVC++2010 to the Boost root directory and have an #include <boost/regex.hpp> in my source code. I set a library directory to boost\stage\lib but there are hundreds of files in there – several for each Boost library and these for boost::regex:

libboost_regex-vc100-s-1_46.lib
libboost_regex-vc100-mt-gd-1_46.lib
libboost_regex-vc100-mt-1_46.lib
libboost_regex-vc100-mt-s-1_46.lib
libboost_regex-vc100-mt-s.lib
libboost_regex-vc100-s.lib
libboost_regex-vc100-mt.lib
libboost_regex-vc100-mt-gd.lib

如何MSVC知道所有的lib文件是正确的？如果它会扫描所有的人都为正确的函数签名，这是否意味着从两个不同的来源（而不是相互链接），它发生在定义具有相同名称和参数的功能，不能在一个lib文件夹编译2个不同的lib的？

How does MSVC know which of all lib files is the right one? If it scans all of them for the right function signatures, does that mean that 2 different lib's compiled from two different sources (not linked to each other) which happen to define functions with identical names and parameters cannot be in one lib folder?

和它如何知道哪个是所有这些不同的正则表达式的.lib的中吧？然后，用 1_46 每个文件在其文件名似乎等同于没有各自的文件，我可以安全地删除其中的两个？

And how does it know which is right among all those different regex .lib's? And then, each file with 1_46 in its filename seems to be identical to the respective file without, can I safely delete one of the two?

推荐答案

Boost库使用一些的黑暗魔法的选择库，从头部和编译器选项链接。我真的不知道所有的血淋淋的细节，但你可以看看升压/配置/ auto_link.hpp头的额外信息。

The boost libraries use some dark magic to select the libraries to link from the headers and compiler options. I don't really know all the gory details, but you can take a look at the boost/config/auto_link.hpp header for extra information.

在特定的，这似乎是难题中的重要部分：

In particular, this seems to be an important piece of the puzzle:

#  pragma comment(lib, BOOST_LIB_PREFIX BOOST_STRINGIZE(BOOST_LIB_NAME) "-" BOOST_LIB_TOOLSET BOOST_LIB_THREAD_OPT BOOST_LIB_RT_OPT "-" BOOST_LIB_VERSION ".lib")

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