具有自动生成的源的Cmake可执行文件 [英] Cmake executable with auto-generated sources

问题描述

我想从例如test_runner.cpp生成可执行文件：

I want to make an executable from, for example, test_runner.cpp:

add_executable(myexe ${CMAKE_CURRENT_BINARY_DIR}/test_runner.cpp)

但是这个特殊的cpp文件本身是在预构建命令中自动生成的：

But this particular cpp file is itself auto-generated in a pre-build command:

add_custom_command(
    TARGET myexe PRE_BUILD
    COMMAND deps/cxxtest-4.4/bin/cxxtestgen --error-printer -o "${CMAKE_CURRENT_BINARY_DIR}/test_runner.cpp" src/My_test_suite.h
    WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
)

但是现在我无法生成新的cmake构建文件，因为它抱怨缺少源，实际上在进行预构建之前就一直没有。

But now I can't generate new cmake build files because it complains about the missing source, which is indeed missing until pre-build.

推荐答案

问题的症结在于应用 GENERATED 属性以进行测试_runner.cpp。这告诉CMake不要在配置时检查它的存在，因为它是在构建过程中创建的。

The crux of the issue is to apply the GENERATED property to "test_runner.cpp". This tells CMake not to check for its existence at configure time, since it gets created as part of the build process.

您可以手动应用此属性（例如，使用 set_source_files_properties ）。但是，解决此问题的正确方法是使用 add_custom_command ，即 add_custom_command（OUTPUT ...）而不是 add_custom_command（TARGET ...）。

You can apply this property manually (e.g. using set_source_files_properties). However, the proper way to handle this is to use the other form of add_custom_command, i.e. add_custom_command(OUTPUT ...) rather than add_custom_command(TARGET ...).

如果指定 test_runner.cpp 作为 add_custom_command（OUTPUT ...）调用的输出，那么使用它的任何目标（在本例中为 myexe）都会导致在调用该自定义命令之前

If you specify "test_runner.cpp" as the output of the add_custom_command(OUTPUT ...) call, then any target consuming it (in this case "myexe") will cause the custom command to be invoked before that target is built.

所以您真的只需要将代码更改为以下内容：

So you really only need to change your code to something like:

set(TestRunner "${CMAKE_CURRENT_BINARY_DIR}/test_runner.cpp")
add_executable(myexe ${TestRunner})
add_custom_command(
    OUTPUT ${TestRunner}
    COMMAND deps/cxxtest-4.4/bin/cxxtestgen --error-printer -o "${TestRunner}" src/My_test_suite.h
    WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}"
)

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