The documentation for the $<COMMAND_CONFIG:...>
generator expression (introduced in CMake 3.20) is a bit ambiguous regarding where it is allowed to be used. It states the following:
Only valid in
add_custom_command()
andadd_custom_target()
as the outer-most generator expression in an argument.
What is meant by “argument” here? Does this mean that it can only appear in a COMMAND
, or does “argument” refer to any argument of add_custom_command()
or add_custom_target()
? Put another way, is it legal to use $<COMMAND_CONFIG:...>
in something listed after DEPENDS
?
This arose in a recent Qt code review. It would be nice to get clarification so we understand what is intended to be formally supported and what isn’t.