[CMake] What is the preferred method of establishing the dependence of a custom command on an executable target?

[Brandon J. Van Every]

Alan W. Irwin wrote:
>
> What do you think of the possibility of using the above "forked" 
> arrangement
> of dependencies instead?  I will go to that (and not worry about
> GET_TARGET_PROPERTY),

You must use GET_TARGET_PROPERTY to support MSVC.  YMMV with other 
generators.

> if anybody can assure me that the executable will
> always be built first before the custom command that requires it.


I'm having trouble with what your ASCII diagram really means.  So, I 
will specify what you have to do in CMake code.

ADD_EXECUTABLE(doit ${DOIT_SOURCES})
GET_TARGET_PROPERTY(DOIT_EXE doit LOCATION)

ADD_CUSTOM_COMMAND(
  OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/foo0.qaz
  COMMAND ${DOIT_EXE} ${CMAKE_CURRENT_SOURCE_DIR}/someinput0.txt  
${CMAKE_CURRENT_BINARY_DIR}/foo0.qaz
)
ADD_CUSTOM_COMMAND(
  OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/foo1.qaz
  COMMAND ${DOIT_EXE} ${CMAKE_CURRENT_SOURCE_DIR}/someinput1.txt  
${CMAKE_CURRENT_BINARY_DIR}/foo1.qaz
)
[...]
ADD_CUSTOM_COMMAND(
  OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/fooN.qaz
  COMMAND ${DOIT_EXE} ${CMAKE_CURRENT_SOURCE_DIR}/someinputN.txt  
${CMAKE_CURRENT_BINARY_DIR}/fooN.qaz
)

SET(FOO_FILES_LIST
  ${CMAKE_CURRENT_BINARY_DIR}/foo0.qaz
  ${CMAKE_CURRENT_BINARY_DIR}/foo1.qaz
  [...]
  ${CMAKE_CURRENT_BINARY_DIR}/fooN.qaz
 )

# The DEPENDS are file level dependencies.  By wrapping them with 
ADD_CUSTOM_TARGET,
# you have created a target level dependency for all of them.
ADD_CUSTOM_TARGET(foo-files DEPENDS ${FOO_FILES_LIST})
# Make sure ${DOIT_EXE} is built before trying to produce the files.
ADD_DEPENDENCIES(foo-files doit)

# Now we can get on with making our library.
ADD_LIBRARY(libwhatever ${FOO_FILES_LIST})


Cheers,
Brandon Van Every