Boost's auto link mechanism and configuration

When we use boost , if we need to link some libraries , We do not have to manually link, in the final analysis or boost auto_link This mechanism, in the boost Under the auto_link.hpp This folder, basically you can see what macro definition to control the boost to link what library, such as Lib library from the beginning of the library compiled Lib , if there is no Lib start, it is a dynamic library, when installed on the client, we need to bring the corresponding DLL

// // Select linkage opt: // #if (Defined (_dll) | | defined (_rtldll)) && defined (boost_dyn_link)#  define Boost_lib_prefix# elif defined (boost_dyn_link)#  "Mixing a DLL BOOST library with a static runtime is a Rea lly Bad idea ... " #else #   " Lib " #endif

From here we can see that if you do not define _dll or boost_dyn_link, then BOOST will automatically select the static library

But there's a place where the egg hurts, because if you include a boost library header file, like python, then boost will automatically trigger the link, See the following code specifically

#ifdef boost_auto_link_tagged# pragma comment (lib, boost_lib_prefix Boost_stringize (boost_lib_name) boost_lib_ Thread_opt boost_lib_rt_opt". Lib") # ifdef boost_lib_diagnostic# pragma message ("linking to lib file:"Boost_lib_prefix boost_stringize (boost_lib_name) boost_lib_thread_opt boost_lib_rt_opt". Lib") # endif#elifDefined (Boost_auto_link_nomangle)# pragma comment (lib, boost_stringize (boost_lib_name)". Lib") # ifdef boost_lib_diagnostic# pragma message ("linking to lib file:"Boost_stringize (Boost_lib_name)". Lib") # endif#else# 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") # ifdef boost_lib_diagnostic# pragma message ("linking to lib file:"Boost_lib_prefix boost_stringize (Boost_lib_name)"-"Boost_lib_toolset boost_lib_thread_opt boost_lib_rt_opt"-"Boost_lib_version". Lib") # endif#endif

so in the development of the time we often meet this situation, named a project has been linked to the Lib Python library, but he still go to link python dll Library, this is because you specify in a project to link python Lib library, and because of the C + + include mechanism, as long as you have a file in the other project recursive include contains Python header file, then it triggers this automatic link mechanism, but does not specify a link static library in another project, it will let another project run to link DLL, so we need to define these two macro definitions

Boost_python_static_module

Boost_python_static_lib

In most of the library directory, there will be a config.hpp, which is responsible for the configuration of a single library of some macro definitions, if you need to know which libraries have what configuration, open this file to see it.

Boost's auto link mechanism and configuration