Cmake:基于变量内容的 add_custom_command 参数

Question

我想要一个 Cmake 函数来将一些二进制文件复制到特定位置。为此，我有以下函数定义:

function ( collect_binaries TARGET_NAME DEST_DIR )
   set ( targetsToCopy ${ARGN} )

   set ( copy_cmd "COMMAND ${CMAKE_COMMAND} -E make_directory ${DEST_DIR}\n" )

   foreach ( target ${targetsToCopy} )
      LIST( APPEND copy_cmd "COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_FILE:${target}> ${DEST_DIR}$<TARGET_FILE_NAME:${target}>\n")
   endforeach( target ${targetsToCopy} )

   #message( FATAL_ERROR ${copy_cmd} )
   add_custom_target( ${TARGET_NAME} )
   add_custom_command( TARGET ${TARGET_NAME} PRE_BUILD ${copy_cmd} )

endfunction( collect_binaries )

以及以下用法:

collect_binaries( bin_copy ${PROJECT_BINARY_DIR}/out/ target_1 target_2 target3 )

我在项目树中定义了 target_1、target_2 和 target_3。考虑到这一点，我得到了以下 Cmake 配置输出:

CMake Warning (dev) at binary_copy.cmake:15 (add_custom_command):

Policy CMP0040 is not set: The target in the TARGET signature of add_custom_command() must exist. Run "cmake --help-policy CMP0040" for policy details. Use the cmake_policy command to set the policy and suppress this warning.

在这种情况下，目标似乎是未知的……但它确实存在并且没有错字。这里有什么问题？

Answer 1

您正在设置 copy_cmd collect_binaries 中的变量用作 CMake 字符串。 add_custom_command但是需要一个 CMake 列表来正确解析参数，即:

function ( collect_binaries TARGET_NAME DEST_DIR )
   set ( targetsToCopy ${ARGN} )

   set ( copy_cmd COMMAND ${CMAKE_COMMAND} -E make_directory ${DEST_DIR} )

   foreach ( target ${targetsToCopy} )
      LIST( APPEND copy_cmd COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_FILE:${target}> "${DEST_DIR}$<TARGET_FILE_NAME:${target}>")
   endforeach( target ${targetsToCopy} )

   #message( FATAL_ERROR ${copy_cmd} )
   add_custom_target( ${TARGET_NAME} )
   add_custom_command( TARGET ${TARGET_NAME} PRE_BUILD ${copy_cmd} )

endfunction( collect_binaries )