这是一个非常微不足道的问题,可能是由于我对 CMake 缺乏经验。我已按照 http://fabzter.com/blog/cmake-tutorial-1 上的教程进行操作并且遇到链接问题。
基本上我有一个库 MathFuncs 和一个使用 MathFuncs 的可执行文件。 MathFuncs 的 CMakeLists 是:
cmake_minimum_required(VERSION 2.8)
project(MathFuncs)
include_directories(${PROJECT_SOURCE_DIR})
SET (HEADER_FILES mysqrt.hpp)
add_library(MathFuncs SHARED mysqrt.cpp ${HEADER_FILES})
可执行的 CMakeLists 是:
cmake_minimum_required (VERSION 2.6)
project (Tutorial)
set (Tutorial_VERSION_MAJOR 1)
set (Tutorial_VERSION_MINOR 0)
set (Tutorial_VERSION_BUGFIX 0)
#configure header file to pass some of the CMake settings
#to the source code
configure_file(
"${PROJECT_SOURCE_DIR}/TutorialConfig.h.in"
"${PROJECT_BINARY_DIR}/TutorialConfig.h"
)
# add the binary tree to the search path for include files
# so that we will find TutorialConfig.h
include_directories("${PROJECT_BINARY_DIR}")
# add the include directories necessary to build library
include_directories("${PROJECT_SOURCE_DIR}/MathFuncs}")
add_subdirectory(MathFuncs)
SET (MATHFUNCTIONS_DIR ${PROJECT_SOURCE_DIR}/MathFuncs)
add_executable(tutorial tutorial.cpp ${MATHFUNCTIONS_DIR}/mysqrt.hpp)
target_link_libraries(tutorial MathFuncs)
CMake 运行良好。但是,当我尝试使用 Visual Studio 进行编译时,出现链接器错误,指出它无法打开 MathFuncs.lib。当我从 MathFuncs CMakeList 中删除“SHARED”选项时,它会运行,因为它正在构建一个静态库,但是对于我的应用程序,我想要一个共享库 DLL。
如何让 CMake 将库引用设置为共享?
谢谢,
最佳答案
看起来您没有正确地从 DLL 中导出类/函数。参见 this article获取详细说明。
这并不完全简单,但幸运的是 CMake 可以在这里提供一些帮助。您可以使用 GenerateExportHeader
模块自动生成一个 header ,其中包含正确导出库的公共(public)函数所需的所有预处理器定义。
这是我如何更改您的文件的示例。希望每个人都得到足够的评论,让您了解发生了什么。如果没有,请添加评论,我会展开。
顶级 CMakeLists.txt:
cmake_minimum_required (VERSION 3.0)
project(Tutorial)
add_subdirectory(MathFuncs)
set(Tutorial_VERSION_MAJOR 1)
set(Tutorial_VERSION_MINOR 0)
set(Tutorial_VERSION_BUGFIX 0)
# Configure header file to pass some of the CMake settings to the source code.
set(TutorialConfigHeader "${PROJECT_BINARY_DIR}/TutorialConfig.h")
configure_file(TutorialConfig.h.in "${TutorialConfigHeader}")
# Include the output file of 'configure_file' to ensure it gets configured.
add_executable(tutorial tutorial.cpp "${TutorialConfigHeader}")
# Add TutorialConfig.h's path to include dirs for 'tutorial'.
target_include_directories(tutorial PRIVATE "${PROJECT_BINARY_DIR}")
target_link_libraries(tutorial MathFuncs)
# If 'MathFuncs' is a shared lib, copy it to 'tutorial's bin dir so
# it can be found at runtime.
get_target_property(MathFuncsType MathFuncs TYPE)
if(MathFuncsType STREQUAL "SHARED_LIBRARY")
add_custom_command(TARGET tutorial POST_BUILD
COMMAND ${CMAKE_COMMAND} -E copy_if_different
$<TARGET_FILE:MathFuncs> $<TARGET_FILE_DIR:tutorial>
COMMENT "Copying MathFuncs shared lib alongside tutorial."
VERBATIM)
endif()
MathFuncs/CMakeLists.txt:
cmake_minimum_required(VERSION 3.0)
project(MathFuncs)
add_library(MathFuncs SHARED
mysqrt.cpp
mysqrt.hpp
"${PROJECT_BINARY_DIR}/mathfuncs_export.h")
# Write appropriate export PP definitions in a file called
# 'mathfuncs_export.h' in the current binary dir
include(GenerateExportHeader)
generate_export_header(MathFuncs)
# Add the current source dir as a PUBLIC include dir
# (to allow mysqrt.hpp to be found by dependent targets)
# Add the current binary dir as a PUBLIC include dir
# (to allow mathfuncs_export.h to be found by dependent targets)
target_include_directories(MathFuncs PUBLIC
${PROJECT_SOURCE_DIR} ${PROJECT_BINARY_DIR})
然后要使用生成的导出 header ,您只需要让 mysqrt.hpp 包含如下内容:
#ifndef MYSQRT_HPP_
#define MYSQRT_HPP_
#include "mathfuncs_export.h"
double MATHFUNCS_EXPORT MySqrt(double input);
#endif // MYSQRT_HPP_
现在这应该会导致 VS 创建导出库 ${CMAKE_BINARY_DIR}/MathFuncs/Debug/MathFuncs.lib
(修复链接器问题)和实际的 DLL $ {CMAKE_BINARY_DIR}/MathFuncs/Debug/MathFuncs.dll
。
关于c++ - 为什么我的共享库在使用 CMake 时链接不正确?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26495564/