Why can CMake ignore add_custom_command? [duplicate]

Question

I have following problem:

In my cmake project I create for each target custom command, that will write its includes in file.

set(TARGET_INCLUDES $<TARGET_PROPERTY:${target},INCLUDE_DIRECTORIES>)
set(INCL_FILE "project_includes/${target}_includes.txt")
set( INC_WRITER_FLAGS --include-path ${CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES} ${TARGET_INCLUDES}
                          --output ${CMAKE_BINARY_DIR}/${INCL_FILE} )

message("!!!!!!!!!!!!! generating rule for ${CMAKE_BINARY_DIR}/${INCL_FILE}")
add_custom_command(
      OUTPUT ${CMAKE_BINARY_DIR}/${INCL_FILE}
      COMMAND ${Python3_EXECUTABLE} ${INCLUDE_WRITER_PATH} ${INC_WRITER_FLAGS}
      VERBATIM)

I see this debug message for each of my targets, so I assume, that it is created. Then for each target I create script that depends on all *_includes.txt of its dependencies. But in my resulting build.ninja there is no command for creating *_includes.txt for about quarter of my targets and build fails as second script cannot find neither its dependencies nor rules to create them. Currently I have no idea, what targets for those add_custom_command didn't do anything have in common, maybe someone have idea, under what circumstances can such effect be possible? Cmake 3.18.5

KamilCuk · Accepted Answer · 2024-07-15 07:58:32Z

1

Add custom command is only run if output is used. When output is not used, it is not run.

See add custom target.

answered Jul 15, 2024 at 7:58

KamilCuk

146k8 gold badges84 silver badges154 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Crazy Sage Over a year ago

But it is used, other add_custom_command explicitly depends on it's output and build fails due to absence of those output (and even rule to build it)

Tsyvarev Over a year ago

@CrazySage: ".. other add_custom_command explicitly depends on it's output" - Please, update your question post to the state of minimal reproducible example. Currently your question post shows only single add_custom_command call and nothing else. Without complete code we have no idea why your project doesn't work.

Collectives™ on Stack Overflow

Why can CMake ignore add_custom_command? [duplicate]

1 Answer 1

2 Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Linked

Related