All,
I’m not sure how to do what I want, so I’m hoping the gurus here can help. In some code where we build Wavewatch in the model I work on, we have CMake like this:
set (WW3ESMF_F90)
foreach(src_file ${WW3ESMF_FTN})
STRING(REGEX REPLACE ".ftn" ".F90" gen_src_file ${src_file})
STRING(REGEX REPLACE "/" "_" gen_log_file ${gen_src_file})
add_custom_command(
OUTPUT ${gen_src_file}
BYPRODUCTS ${gen_src_file}
DEPENDS w3adc ${ftn_dir}/${src_file}
COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/run_w3adc.sh ${ftn_dir} ${src_file} > ${gen_log_file}.w3adc.log 2>&1
COMMENT "Running w3adc ${src_file}")
list(APPEND WW3ESMF_F90 ${gen_src_file})
endforeach()
because the Wavewatch tag we currently use is the older style that had files like constants.ftn that you then used w3adc on to generate constants.f90. Weird, but works. (I think Wavewatch has gotten rid of this but we still have it until the next release.)
Recently I was reminded that Ninja no longer builds our model and I tracked it down to this block and the fact that things build just fine if the BYPRODUCTS line is not in that add_custom_command.
Now the fun part: apparently if I want to build this with GNU plus the Unix Makefiles generator, that BYPRODUCTS is needed!
With some testing I see that:
if (CMAKE_GENERATOR STREQUAL "Unix Makefiles")
set(BYPRODUCTS ${gen_src_file})
else()
set(BYPRODUCTS "")
endif()
add_custom_command(
OUTPUT ${gen_src_file}
BYPRODUCTS ${BYPRODUCTS}
DEPENDS w3adc ${ftn_dir}/${src_file}
COMMAND ${CMAKE_CURRENT_SOURCE_DIR}/run_w3adc.sh ${ftn_dir} ${src_file} > ${gen_log_file}.w3adc.log 2>&1
COMMENT "Running w3adc ${src_file}")
works but it seems…wrong? Works, but wrong.
So, I was wondering if there is any clever generator expression I could use to say “If CMAKE_GENERATOR is Ninja, no BYPRODUCTS, else yes BYPRODUCTS?”