【发布时间】：2015-10-19 08:17:12
【问题描述】：
我写了一个 cmake 文件，它构建了两个共享库一个 vector3.c 和一个 matrix4.c matrix4 取决于 vector3，如果我运行我的 cmake 项目并且只构建它构建的 vector3 共享库，它构建得很好，当我添加 matrix4 共享库时，我得到一个 cmake 错误。没有制定目标的规则。
文件夹结构
core_math
------CMakeLists.txt
-common/
------common_structs.h
-matrix4/
------CMakeLists.txt
------matrix4/src/matrix4_scalar.c
------matrix4/headers/matrix4_scalar.h
-vector3/
-------CMakeLists.txt
-------vector3/src/vector3_scalar.c
-------vector3/headers/vector3_scalar.h
core_math/CMakeLists.txt
PROJECT(core_math)
CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
ADD_SUBDIRECTORY(vector3_scalar)
ADD_SUBDIRECTORY(matrix4_scalar)
SET(CMAKE_ARCHIVE_OUTPUT_DIRECTORY $(CMAKE_BINARY_DIR)/static_lib)
SET(CMAKE_LIBRARY_OUTPUT_DIRECTORY $(CMAKE_BINARY_DIR)/shared_lib)
SET(CMAKE_RUNTIME_OUTPUT_DIRECTORY $(CMAKE_BINARY_DIR)/bin)
SET(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake_modules)
core_math/vector3/CMakeLists.txt
PROJECT(vector3_scalar)
SET(CMAKE_MACOSX_RPATH 1)
INCLUDE_DIRECTORIES(${CMAKE_CURRENT_SOURCE_DIR}/../common)
SET(HEADER_FILES ${CMAKE_CURRENT_SOURCE_DIR}/../common/common_structs.h)
SET(SRC_FILES ${CMAKE_CURRENT_SOURCE_DIR}/src/vector3_scalar.c ${HEADER_FILES})
ADD_LIBRARY(vector3_scalar SHARED ${SRC_FILES})
core_math/matrix4_scalar/CMakeLists.txt
PROJECT(matrix4_scalar)
SET(CMAKE_MACOSX_RPATH 1)
INCLUDE_DIRECTORIES(${CMAKE_CURRENT_SOURCE_DIR}/../common
${CMAKE_CURRENT_SOURCE_DIR}/../vector3_scalar)
SET(HEADER_FILES ${CMAKE_CURRENT_SOURCE_DIR}/../common/common_structs.h
${CMAKE_CURRENT_SOURCE_DIR}/../vector3_scalar/headers/vector3_scalar.h
${CMAKE_CURRENT_SOURCE_DIR}/headers/matrix4_scalar.h)
SET(SRC_FILES ${CMAKE_CURRENT_SOURCE_DIR}/src/matrix4_scalar.c ${HEADER_FILES})
ADD_LIBRARY(matrix4_scalar SHARED ${SRC_FILES})
TARGET_LINK_LIBRARIES(matrix4_scalar vector3_scalar)
编译错误
-- Build files have been written to: /Users/blubee/MATH/project/build
Scanning dependencies of target vector3_scalar
[ 25%] Building C object source/core_math/vector3_scalar/CMakeFiles/vector3_scalar.dir/sr
c/vector3_scalar.c.o
[ 50%] Linking C shared library $(CMAKE_BINARY_DIR)/lib/libvector3_scalar.dylib
[ 50%] Built target vector3_scalar
Scanning dependencies of target matrix4_scalar
[ 75%] Building C object source/core_math/matrix4_scalar/CMakeFiles/matrix4_scalar.dir/sr
c/matrix4_scalar.c.o
make[2]: *** No rule to make target `source/core_math/vector3_scalar//Users/blubee/MATH/pr
oject/build/lib/libvector3_scalar.dylib', needed by `source/core_math/matrix4_scalar//Use
rs/blubee/MATH/project/build/lib/libmatrix4_scalar.dylib'. Stop.
make[1]: *** [source/core_math/matrix4_scalar/CMakeFiles/matrix4_scalar.dir/all] Error 2
make: *** [all] Error 2
如果我从 matrix4_scalar cmakelists.txt 文件中删除 target_link_libraries，则会收到未定义符号错误。
Undefined symbols for architecture x86_64:
"_vec3_deg2rad", referenced from:
_mat4_rotate in matrix4_scalar.c.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [source/core_math/matrix4_scalar//Users/blubee/MATH/project/build/lib/libmatr
ix4_scalar.dylib] Error 1
make[1]: *** [source/core_math/matrix4_scalar/CMakeFiles/matrix4_scalar.dir/all] Error 2
make: *** [all] Error 2
【问题讨论】：
-
您可以删除 matrix4_scalar/CMakeLists.txt 中的 TARGET_LINK_LIBRARIES() 指令。对于共享库，创建共享库时不需要链接依赖库。
-
我过去尝试过，但我得到未定义的符号，因为 matrix4_scalar 找不到 vector3 函数。
-
如果您将
vector3_scalar.h直接包含在matrix4_scalar.c中，那么您需要为vector3_scalar.h中声明的任何内容定义一些“导出前缀”。否则，liker 会尝试静态链接这些功能。因此，如果您的工具链未提供，您可以使用 CMake 生成这些“导出标头”（请参阅GENERATE_EXPORT_HEADER()宏）。 -
common/common_structs.h 是定义实际结构的地方，然后 matrix4 和 vector3 都可以包含该头文件并避免循环依赖。
标签： c cmake shared-libraries libraries