How best to set output directory for a CMake C++ project built by Visual Studio 2017?

问题

I have used Visual Studio 2017 to build C++ desktop projects using .vcxproj files. I like the default behavior where the output directory is a subdirectory below the project. For example:

|-myproj.sln
|-myproj.vcxproj
|-----------------|--x64 --|-- myproj_release --|-- myproj.exe

I now want to define the build using CMake instead of .vcxproj, so that I can build with Visual Studio Code as an alternative to Visual Studio 2017.

I converted my .vcxproj to a CMake project using cmake-converter. The resulting CMakeLists.txt contains:

if(CMAKE_BUILD_TYPE STREQUAL "Debug")
  set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${OUTPUT_DEBUG}")
  set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${OUTPUT_DEBUG}")
  set(CMAKE_EXECUTABLE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${OUTPUT_DEBUG}")
else()
  set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${OUTPUT_REL}")
  set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${OUTPUT_REL}")
  set(CMAKE_EXECUTABLE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/${OUTPUT_REL}")
endif()

When I open this CMakeLists.txt with Visual Studio 2017 and build it, it puts the executable in subdirectory CMakeBuilds of my user directory. I guess this is because Visual Studio 2017 is determining CMAKE_BINARY_DIR.

What is the best way of getting the output directory to be in the source directory as happens with my .vcxproj file?

回答1:

Visual Studio is a multiconfiguration generator. That is, it configures the project for several configurations at once. Because of that, when using such generators the variable CMAKE_BUILD_TYPE doesn't contain the configuration name, it is simply empty.

By default, with multiconfiguration generators, variables like CMAKE_LIBRARY_OUTPUT_DIRECTORY are automatically appended with per-configuration subdirectory. There are two ways to handle this behaviour:

Use generator expressions when defining the variable. That expression may be evaluated conditionally, depended on the configuration type. E.g.:

# For Debug configuration this will be evaluated to
#   '${CMAKE_BINARY_DIR}/${OUTPUT_DEBUG}'
# For Release configuration this will be evaluated to
#   '${CMAKE_BINARY_DIR}/${OUTPUT_REL}'
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/<$<$CONFIG:DEBUG$>:${OUTPUT_DEBUG}$><$<$CONFIG:RELEASE$>:${OUTPUT_REL}$>")

Use _<CONFIG> versions of the variable. E.g.:

# Output directory for libraries in Debug configuration
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY_DEBUG ${CMAKE_BINARY_DIR}/${OUTPUT_DEBUG})
# Output directory for libraries in Release configuration
set(CMAKE_LIBRARY_OUTPUT_DIRECTORY_RELEASE ${CMAKE_BINARY_DIR}/${OUTPUT_REL})

回答2:

I think the answer for my question is to modify buildRoot in CmakeSettings.json:

"buildRoot": "${workspaceRoot}\\build\\${name}"

来源：https://stackoverflow.com/questions/56477504/how-best-to-set-output-directory-for-a-cmake-c-project-built-by-visual-studio

标签

c++

visual-studio

cmake