Question

In my project I have a “schema” file and utility that I wrote to generate a header file.
I’m using cmake and out of source build to build the application.

Currently I have to regenerate the header file by hand then build the application.

Then I came up with this CMakeLists.txt statements, but they generate the header in the build directory instead of in the source directory.

configure_file( generator.pl generator COPYONLY )
configure_file( schema.txt.in schema.txt COPYONLY )
add_custom_command(
    OUTPUT generated.h
    COMMAND ./generator schema.txt generated.h
    DEPENDS mib_schema.txt.in generator.pl
    COMMENT "Regenerating header file..."
)

Is it possible to generate the header in the source directory?

edit (to reflect the answer):

The file can be reached directly by fully qualifying its path with either

${CMAKE_CURRENT_SOURCE_DIR}

or:

${CMAKE_CURRENT_BINARY_DIR}

So, to generate the header in my source dir, the previous excerpt from CMakeLists.txt becomes:

add_custom_command(
    OUTPUT generated.h
    COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/generator.pl ${CMAKE_CURRENT_SOURCE_DIR}/schema.txt.in ${CMAKE_CURRENT_SOURCE_DIR}/generated.h
    DEPENDS mib_schema.txt.in generator.pl
    COMMENT "Regenerating header file..."
)

which is actually simpler.
Thanks

–to

Answer 1

I think that generated header are well placed in the binary directory, since you might want to create to build directories with the same source and different configurations resulting in different header generated.

You might want to include the build directory to your project:

include_directories(${CMAKE_CURRENT_BINARY_DIR})