使用共享库版本的 CMake 最佳实践

Question

我正在组织我的“C 语言开发策略”并在静态和共享库中分发一些代码。

静态库没问题，但我在文档中发现了关于共享库的“空白”：如何在“find_library”上指定 SOVERSION。

此时我正在以这种方式构建库：

cmake_minimum_required (VERSION 2.8.11)

set (INSTALL_BIN_DIR "" CACHE PATH "full binary path")
set (INSTALL_LIB_DIR "$ENV{HOME}/embedded/llib/lib" CACHE PATH "full binary path")
set (INSTALL_INCLUDE_DIR "$ENV{HOME}/embedded/llib/include" CACHE PATH "full include path")
set (SRC_DIR "src" CACHE PATH "Source files path")
set (H_DIR  "include" CACHE PATH "Source files path")

set (C_FILES )
list (
    APPEND C_FILES
    ${SRC_DIR}/cJSON.c
    )

set (H_FILES )
list (
    APPEND H_FILES
    ${H_DIR}/cJSON.h
    )

# Define Project name
project (cJSON)

# Create a library called "cJSON" which includes the source and header files.
add_library (cJSON SHARED "${C_FILES}")

#set_target_properties(cJSON PROPERTIES
#   PUBLIC_HEADER "include/cJSON.h")

include_directories (include)
# Make sure the compiler can find include files for our Hello library
# when other libraries or executables link to Hello
#target_include_directories (cJSON PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})

set_target_properties (cJSON 
                        PROPERTIES 
                            VERSION 1.0 SOVERSION 1
                            PUBLIC_HEADER "${H_FILES}" 
                    )

install(TARGETS cJSON 
# IMPORTANT: Add the foo library to the "export-set"
  EXPORT cJSONTargets
  LIBRARY
  RUNTIME DESTINATION "${INSTALL_BIN_DIR}" COMPONENT bin
  LIBRARY DESTINATION "${INSTALL_LIB_DIR}" COMPONENT shlib
  PUBLIC_HEADER DESTINATION "${INSTALL_INCLUDE_DIR}" COMPONENT dev
  )

运行 cmake、make 和 make install 结果：

lrwxrwxrwx 1 takaite takaite    13 Dez  7 11:52 libcJSON.so -> libcJSON.so.1
lrwxrwxrwx 1 takaite takaite    15 Dez  7 11:52 libcJSON.so.1 -> libcJSON.so.1.0
-rw-r--r-- 1 takaite takaite 27194 Dez  7 15:03 libcJSON.so.1.0

在另一个库中，我是这样包含的：

cmake_minimum_required (VERSION 2.8.11)

set (INSTALL_BIN_DIR "" CACHE PATH "full binary path")
set (INSTALL_LIB_DIR "$ENV{HOME}/embedded/llib/lib" CACHE PATH "full binary path")
set (INSTALL_INCLUDE_DIR "$ENV{HOME}/embedded/llib/include" CACHE PATH "full include path")
set (SRC_DIR "src" CACHE PATH "Source files path")
set (H_DIR  "include" CACHE PATH "Source files path")

set (C_FILES )
list (
    APPEND C_FILES
    ${SRC_DIR}/dict.c
    )

set (H_FILES )
list (
    APPEND H_FILES
    ${H_DIR}/dict.h
    )


# Define Project name
project (dict)

set (CMAKE_FIND_LIBRARY_SUFFIXES_BKP ${CMAKE_FIND_LIBRARY_SUFFIXES})
# Set lib version to be used
set (CMAKE_FIND_LIBRARY_SUFFIXES ".so.1")

find_library (
    CJSON_LIB 
    NAMES cJSON 
    PATHS ${INSTALL_LIB_DIR}
    )
set (CMAKE_FIND_LIBRARY_SUFFIXES ${CMAKE_FIND_LIBRARY_SUFFIXES_BKP})

message ("cJSON_lib: ${CJSON_LIB}")

# Create a library called "cJSON" which includes the source and header files.
add_library (dict SHARED "${C_FILES}" ${CJSON_LIB})

include_directories (${H_DIR} ${INSTALL_INCLUDE_DIR})
# Make sure the compiler can find include files for our Hello library
# when other libraries or executables link to Hello
#target_include_directories (cJSON PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})

set_target_properties (dict 
                        PROPERTIES 
                            VERSION 1.0 SOVERSION 1
                            PUBLIC_HEADER "${H_FILES}"
                    )

install(TARGETS dict 
# IMPORTANT: Add the foo library to the "export-set"
  EXPORT DictTargets
  LIBRARY
  RUNTIME DESTINATION "${INSTALL_BIN_DIR}" COMPONENT bin
  LIBRARY DESTINATION "${INSTALL_LIB_DIR}" COMPONENT shlib
  PUBLIC_HEADER DESTINATION "${INSTALL_INCLUDE_DIR}" COMPONENT dev
  )

我不敢相信这是正确的做法。谁能告诉我一个更好的方法？

Answer 1

对于搜索特定库的版本，您可以在NAMES 选项中使用精确文件名find_library：

find_library (
    CJSON_LIB 
    NAMES libcJSON.so.1
    PATHS ${INSTALL_LIB_DIR}
    )

来自find_library 的文档：

赋予 NAMES 选项的每个库名称首先被视为库文件名，然后与特定于平台的前缀（例如 lib）和后缀（例如 .so）一起考虑。因此，可以直接指定库文件名，例如 libfoo.a。这可用于在类 UNIX 系统上定位静态库。

---

请注意，同一库的不同 soversion 被假定为彼此 兼容 ABI。所以很少需要搜索库的特定版本。

库中引入 ABI incopatibility 的更改应伴随更改库的版本。例如：libcJSON2.so。因此，您不会使用 find_library 意外找到 incompatible 库。