C++ 如何使cmake在子文件夹中查找共享库

我正在努力学习如何创建共享库。下面的方法似乎有效（如果你对这种方法有一些反馈，请发表评论，我基本上不知道我在做什么）

在我的库项目中，我将头文件放在名为“include”的文件夹中，将源文件放在“src”中

我的库的CMakeLists.txt：

cmake_minimum_required(VERSION 2.4.0)

project(mycustomlib)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Include header files
include_directories(include)

# Create shared library
add_library(${PROJECT_NAME} SHARED ${SOURCES})

# Install library
install(TARGETS ${PROJECT_NAME} DESTINATION lib)

# Install library headers
file(GLOB HEADERS include/*.h)
install(FILES ${HEADERS} DESTINATION include)

cmake_minimum_required(VERSION 2.4.0)

project(myprogram)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Create executable
add_executable(${PROJECT_NAME} ${SOURCES})

# Find and link library
find_library(MYCUSTOMLIB mycustomlib)
target_link_libraries(${PROJECT_NAME} ${MYCUSTOMLIB})

cmake_minimum_required(VERSION 2.4.0)

project(mycustomlib)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Include header files
include_directories(include)

# Create shared library
add_library(${PROJECT_NAME} SHARED ${SOURCES})

# Install library
install(TARGETS ${PROJECT_NAME} DESTINATION lib/${PROJECT_NAME})

# Install library headers
file(GLOB HEADERS include/*.h)
install(FILES ${HEADERS} DESTINATION include/${PROJECT_NAME})

cmake_minimum_required(VERSION 2.4.0)

project(myprogram)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Create executable
add_executable(${PROJECT_NAME} ${SOURCES})

# Find and link library
find_library(MYCUSTOMLIB mycustomlib/mycustomlib)
target_link_libraries(${PROJECT_NAME} ${MYCUSTOMLIB})

我的应用程序的CMakeLists.txt：

cmake_minimum_required(VERSION 2.4.0)

project(mycustomlib)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Include header files
include_directories(include)

# Create shared library
add_library(${PROJECT_NAME} SHARED ${SOURCES})

# Install library
install(TARGETS ${PROJECT_NAME} DESTINATION lib)

# Install library headers
file(GLOB HEADERS include/*.h)
install(FILES ${HEADERS} DESTINATION include)

cmake_minimum_required(VERSION 2.4.0)

project(myprogram)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Create executable
add_executable(${PROJECT_NAME} ${SOURCES})

# Find and link library
find_library(MYCUSTOMLIB mycustomlib)
target_link_libraries(${PROJECT_NAME} ${MYCUSTOMLIB})

cmake_minimum_required(VERSION 2.4.0)

project(mycustomlib)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Include header files
include_directories(include)

# Create shared library
add_library(${PROJECT_NAME} SHARED ${SOURCES})

# Install library
install(TARGETS ${PROJECT_NAME} DESTINATION lib/${PROJECT_NAME})

# Install library headers
file(GLOB HEADERS include/*.h)
install(FILES ${HEADERS} DESTINATION include/${PROJECT_NAME})

cmake_minimum_required(VERSION 2.4.0)

project(myprogram)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Create executable
add_executable(${PROJECT_NAME} ${SOURCES})

# Find and link library
find_library(MYCUSTOMLIB mycustomlib/mycustomlib)
target_link_libraries(${PROJECT_NAME} ${MYCUSTOMLIB})

这是在工作。问题是，我想将标题和库都放入子文件夹（具体来说：

/usr/local/include/mycustomlib/

用于标题，而

/usr/local/lib/mycustomlib/

用于库）

这就是我的尝试：

我的库的新CMakeLists.txt：

cmake_minimum_required(VERSION 2.4.0)

project(mycustomlib)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Include header files
include_directories(include)

# Create shared library
add_library(${PROJECT_NAME} SHARED ${SOURCES})

# Install library
install(TARGETS ${PROJECT_NAME} DESTINATION lib)

# Install library headers
file(GLOB HEADERS include/*.h)
install(FILES ${HEADERS} DESTINATION include)

cmake_minimum_required(VERSION 2.4.0)

project(myprogram)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Create executable
add_executable(${PROJECT_NAME} ${SOURCES})

# Find and link library
find_library(MYCUSTOMLIB mycustomlib)
target_link_libraries(${PROJECT_NAME} ${MYCUSTOMLIB})

cmake_minimum_required(VERSION 2.4.0)

project(mycustomlib)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Include header files
include_directories(include)

# Create shared library
add_library(${PROJECT_NAME} SHARED ${SOURCES})

# Install library
install(TARGETS ${PROJECT_NAME} DESTINATION lib/${PROJECT_NAME})

# Install library headers
file(GLOB HEADERS include/*.h)
install(FILES ${HEADERS} DESTINATION include/${PROJECT_NAME})

cmake_minimum_required(VERSION 2.4.0)

project(myprogram)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Create executable
add_executable(${PROJECT_NAME} ${SOURCES})

# Find and link library
find_library(MYCUSTOMLIB mycustomlib/mycustomlib)
target_link_libraries(${PROJECT_NAME} ${MYCUSTOMLIB})

我的应用程序的新CMakeLists.txt：

cmake_minimum_required(VERSION 2.4.0)

project(mycustomlib)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Include header files
include_directories(include)

# Create shared library
add_library(${PROJECT_NAME} SHARED ${SOURCES})

# Install library
install(TARGETS ${PROJECT_NAME} DESTINATION lib)

# Install library headers
file(GLOB HEADERS include/*.h)
install(FILES ${HEADERS} DESTINATION include)

cmake_minimum_required(VERSION 2.4.0)

project(myprogram)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Create executable
add_executable(${PROJECT_NAME} ${SOURCES})

# Find and link library
find_library(MYCUSTOMLIB mycustomlib)
target_link_libraries(${PROJECT_NAME} ${MYCUSTOMLIB})

cmake_minimum_required(VERSION 2.4.0)

project(mycustomlib)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Include header files
include_directories(include)

# Create shared library
add_library(${PROJECT_NAME} SHARED ${SOURCES})

# Install library
install(TARGETS ${PROJECT_NAME} DESTINATION lib/${PROJECT_NAME})

# Install library headers
file(GLOB HEADERS include/*.h)
install(FILES ${HEADERS} DESTINATION include/${PROJECT_NAME})

cmake_minimum_required(VERSION 2.4.0)

project(myprogram)

# Find source files
file(GLOB SOURCES src/*.cpp)

# Create executable
add_executable(${PROJECT_NAME} ${SOURCES})

# Find and link library
find_library(MYCUSTOMLIB mycustomlib/mycustomlib)
target_link_libraries(${PROJECT_NAME} ${MYCUSTOMLIB})

这是不起作用的。现在，我被迫指定库的.so文件，如下所示：

find_库（MYCUSTOMLIB-MYCUSTOMLIB/libmycustomlib.so）

---

怎么会呢？

我会先处理您的实际问题，然后再提供其他意见。从技术上讲，您要求CMake查找一个名为

mycustomlib/mycustomlib

的库，但您真正想说的是您想要查找

mycustomlib

，它可以在名为

mycustomlib

的子目录中找到。在第二种情况下，调用

find_library（）

以实现此目的的两种替代方法是：

find_library(MYCUSTOMLIB mycustomlib PATH_SUFFIXES mycustomlib)
find_library(MYCUSTOMLIB mycustomlib PATHS /usr/local/lib/mycustomlib)

target_include_directories(${PROJECT_NAME} PUBLIC include)

后者对库的安装位置做了更多的假设，因此我倾向于第一种选择。第一个选项假设CMake已经在/usr/local/lib中找到了库，这似乎是您的问题。通过修改和，可以影响CMake查找库的位置。我希望上述任何一种选择都能让你的第二个案例奏效

现在来看其他观察结果。您已经在每个

CMakeLists.txt

文件的第一行请求了一个非常旧的最低CMake版本。你可能想至少考虑一下这个2.8（个人建议，我更喜欢3.2或更晚，但是这取决于你的项目需要支持什么）。 您已经使用文件全局绑定来获取源和头的列表。这是不可靠的，通常应该避免（参见对此的讨论）。为了简单起见，您将看到许多示例代码使用此方法，但不建议将其用于实际项目（甚至包括CMake文档）。如果需要健壮的构建，请分别明确列出源文件和头文件

如果您愿意要求CMake 2.8.11或更高版本（现在应该是这样），而不是调用

include_directories（）

，这会使所有内容都选择您指定的标题搜索路径，您应该更愿意将搜索路径要求附加到需要它的目标。你和我一起做这件事。上述代码的等效代码为：

find_library(MYCUSTOMLIB mycustomlib PATH_SUFFIXES mycustomlib)
find_library(MYCUSTOMLIB mycustomlib PATHS /usr/local/lib/mycustomlib)

target_include_directories(${PROJECT_NAME} PUBLIC include)

随着项目规模和复杂性的增加，这可以更好地控制目标间的依赖关系。关于这个话题的更深入的讨论，请参阅，也许也可以（披露：我写了这两篇文章）

您的库和程序是否完全独立于源代码存储库？它们可以在同一个项目中建造吗？您可以在一个

CMakeLists.txt

文件中构建多个目标。项目名称不必与任何目标的名称有任何关系（在简单的示例中，您经常会看到

project\u name

变量重复用于目标名称，这是不幸的，因为它表明两者之间存在关系，但对于除简单项目外的所有项目，情况并非如此）。如果它们在同一个存储库中，那么将它们构建在一起将是一个简单得多的构建，因为您不必安装库来查找并链接可执行文件

如果它们必须在单独的项目中构建，那么应用程序项目的以下内容应该可以帮助您实现：

cmake_minimum_required(VERSION 2.8.11)
project(myprogram)

# List your program's sources here explicitly
add_executable(myprogram src/foo.cpp src/bar.cpp)

# Find and link library
find_library(MYCUSTOMLIB mycustomlib PATH_SUFFIXES mycustomlib)
target_link_libraries(myprogram PUBLIC ${MYCUSTOMLIB})

# Find library's headers and add it as a search path.
# Provide the name of one header file you know should
# be present in mycustomlib's include dir.
find_path(MCL_HEADER_PATH mycustomlib.h PATH_SUFFIXES mycustomlib)
target_include_directories(myprogram PUBLIC ${MCL_HEADER_PATH})

对于额外的点，您可以通过检查公共路径前缀来确认头路径与库位于同一区域，或者您可以直接派生 通过假定目录结构，从MYCUSTOMLIB路径获取MCL_头_路径。这两种方法都有优点和缺点。如果您想探索后者，命令将是您的朋友

---

希望这能为您指明正确的方向。

谢谢！如何包含标题子目录？这就是

target\u include\u directories（）

的作用。在上面，我展示了在构建

${PROJECT\u NAME}

目标时如何将

include

目录添加到头搜索路径。如果您要添加的目录被指定为相对路径，那么CMake文档实际上不会说明它们与构建相关的内容（它们只提到它们与安装相关的内容）。您可能需要进行实验，以了解行为是什么。如果您没有获得预期的行为，请尝试

${CMAKE\u CURRENT\u SOURCE\u DIR}/include

，而不仅仅是

include

。好的，我猜该命令是针对我的库的CMakeLists.txt的。但我仍然不明白如何在我的应用程序的CMakeLists.txt.Answer中指定库头子目录，更新后的答案演示了一种将库头目录添加到程序头搜索路径的方法。太棒了，谢谢！但愿我能投超过1票。