CMake：使静态库有效，但动态库不起作用

CMake: Make a static library works but dynamic doesn't

本文关键字：动态 不起作用 有效 静态 CMake      更新时间：2023-10-16

我正在尝试使用cmake制作共享库，但是它的连线是如果我静态地进行，它可以很好地工作，但是动态却不能：

CMAKE_MINIMUM_REQUIRED(VERSION 3.6)
PROJECT(TestDemo)
SET(CMAKE_CXX_STANDARD 11)
SET(CMAKE_CXX_COMPILER clang++)
# Headers
INCLUDE_DIRECTORIES(src)
INCLUDE_DIRECTORIES(src/xxx)
INCLUDE_DIRECTORIES(3rdparty/zstd)
INCLUDE_DIRECTORIES(/usr/local/include)
# CORE LIB
FILE(GLOB CORE_SRC src/xxx/*.cpp
        src/xxx/io/*.cpp
        src/xxx/util/*.cpp
        src/xxx/thread/*.cpp)
LIST(REMOVE_ITEM CORE_SRC ${CMAKE_CURRENT_SOURCE_DIR}/src/xxx/io/BzipStream.cpp
        ${CMAKE_CURRENT_SOURCE_DIR}/src/xxx/io/GzipStream.cpp)
# This works
ADD_LIBRARY(xxx-core STATIC ${CORE_SRC})
# This doesn't
#ADD_LIBRARY(xxx-core SHARED ${CORE_SRC})

错误消息是：

[100%] Linking CXX shared library libxxxdb-core.dylib
Undefined symbols for architecture x86_64:
  "_mpool_get_global", referenced from:
      xxx::mpoolxx<xxx::alloc_to_mpool_bridge<xxx::mpoolxx<long>, 1>::MemBlock>::get_vtab() in trb_cxx.cpp.o
  "_sfixed_mpool_destroy", referenced from:
      xxx::fixed_mpool_wrapper<24>::~fixed_mpool_wrapper() in trb_cxx.cpp.o
  "_sfixed_mpool_init", referenced from:
      xxx::fixed_mpool_wrapper<24>::fixed_mpool_wrapper() in trb_cxx.cpp.o
  "_trb_destroy", referenced from:
      xxx::trbstrmap_imp<int, unsigned char, &(xxx_trb_compare_less_tag), xxx::mpoolxx<long>, 0, 16>::~trbstrmap_imp() in trb_cxx.cpp.o
      xxx::trbtab<int const, std::__1::pair<int const, int>, 0, &(xxx_trb_compare_less_tag), xxx::fixed_mpoolxx<long>, 0, 16>::~trbtab() in trb_cxx.cpp.o
  "_trb_erase", referenced from:
      xxx::trbtab<int const, std::__1::pair<int const, int>, 0, &(xxx_trb_compare_less_tag), xxx::fixed_mpoolxx<long>, 0, 16>::erase(int const&) in trb_cxx.cpp.o
      xxx::trbtab<int const, std::__1::pair<int const, int>, 0, &(xxx_trb_compare_less_tag), xxx::fixed_mpoolxx<long>, 0, 16>::erase(xxx::trb_iterator<std::__1::pair<int const, int>, 16, 0>) in trb_cxx.cpp.o
  "_trb_iter_first", referenced from:
      xxx::trbtab<int const, std::__1::pair<int const, int>, 0, &(xxx_trb_compare_less_tag), xxx::fixed_mpoolxx<long>, 0, 16>::begin() const in trb_cxx.cpp.o
  "_trb_iter_next", referenced from:
      xxx::trb_iterator<std::__1::pair<int const, int>, 16, 0>::operator++() in trb_cxx.cpp.o
  "_trb_probe", referenced from:
      xxx::trbtab<int const, std::__1::pair<int const, int>, 0, &(xxx_trb_compare_less_tag), xxx::fixed_mpoolxx<long>, 0, 16>::insert(std::__1::pair<int const, int> const&) in trb_cxx.cpp.o
      xxx::trbmap<int, int, &(xxx_trb_compare_less_tag), xxx::fixed_mpoolxx<long>, 0, 16>::operator[](int const&) in trb_cxx.cpp.o
  "_trb_probe_node", referenced from:
      xxx::trbstrmap_imp<int, unsigned char, &(xxx_trb_compare_less_tag), xxx::mpoolxx<long>, 0, 16>::probe_raw(char const*, unsigned long, char const*) in trb_cxx.cpp.o
  "_trb_vtab_init", referenced from:
      xxx::trbxx_vtab_init_by_cxx_type(trb_vtab*, field_type_t, int (*)(trb_vtab const*, trb_tree const*, void const*, void const*), int (*)(trb_vtab const*, trb_tree const*, void const*, void const*)) in trb_cxx.cpp.o
      xxx::trbxx_vtab_init(trb_vtab*, field_type_t, int (*)(trb_vtab const*, trb_tree const*, void const*, void const*)) in trb_cxx.cpp.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

在静态库的创建中没有链接发生，因为静态库不是链接器生成的：它只是创建对象文件的档案与档案馆ar。所以不能创建静态库时，是任何未定义的引用或其他链接错误，就像您创建对象文件的.tar或.zip档案库一样，无法进行。请参阅静态上线，

共享库，例如程序，是链接器和Mac OS/darwin生产的链接器（与GNU/Linux Linker不同）默认情况下不允许未定义的符号共享库中的参考。

您有两个选择：

您可以指定xxx-core依赖其链接的所有库，使用target_link_libraries

或，您可以使用链接选项覆盖链接器的默认行为 -undefined=dynamic_lookup，指示共享库中未定义的引用将在运行时由加载程序解决。在您的cmakelists.txt中，使用set_target_properties定义xxx-core目标后：

ADD_LIBRARY(xxx-core SHARED ${CORE_SRC})
SET_TARGET_PROPERTIES(xxx-core LINK_FLAGS Wl,-undefined=dynamic_lookup)
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