Question

我很难理解CMake的导入库。这是我的测试结构：

├── binary
│   ├── CMakeLists.txt
│   └── main.cc
├── library
│   ├── CMakeLists.txt
│   ├── lib.cc
│   └── lib.hh

图书馆的CMakeLists.txt如下所示：

cmake_minimum_required(VERSION 2.8.1)

project(Library)

add_library(library lib.cc)
target_include_directories(library PUBLIC ${CMAKE_CURRENT_LIST_DIR})

二进制文件看起来像这样：

cmake_minimum_required(VERSION 2.8.1)

project(binary)

add_executable(binary main.cc)

find_library(il_default library PATHS "${CMAKE_CURRENT_LIST_DIR}/../library/build/")

add_library(Imported::Library UNKNOWN IMPORTED GLOBAL)
set_property(TARGET Imported::Library PROPERTY IMPORTED_LOCATION ${il_default})
set_property(TARGET Imported::Library PROPERTY INTERFACE_INCLUDE_DIRECTORIES "${CMAKE_CURRENT_LIST_DIR}/../library")

target_link_libraries(binary Imported::Library)

构建命令：

cmake -Blibrary/build -Hlibrary && cmake --build library/build
cmake -Bbinary/build -Hbinary && cmake --build binary/build

这会产生以下错误：

CMake Error at CMakeLists.txt:13 (target_link_libraries):
  Target "Imported::Library" of type UNKNOWN_LIBRARY may not be linked into
  another target.  One may link only to STATIC or SHARED libraries, or to
  executables with the ENABLE_EXPORTS property set.

从 add_library 命令中删除 GLOBAL 参数，或用 STATIC 替换 UNKNOWN 解决了这个问题。

我的问题是“为什么？”。为什么我可以在当前目录中使用未知的导入库但不能使其成为全局？

CMake版本是3.6.0

CMake IMPORTED UNKNOWN GLOBAL目标

0 个答案: