Custom command output location

Code
1

When using a multi-config generator like Visual Studio, objects and libraries are (by default) placed in ${CMAKE_CURRENT_BINARY_DIR}/$<CONFIG>. Now, suppose I have a library target, myLib and I want to process it with some script ${PROJECT_SOURCE_DIR}/tools/process.bat and place its output next to myLib. I try:

add_custom_command(
    OUTPUT $<TARGET_FILE_DIR:myLib>/myLib.txt
    COMMAND ${PROJECT_SOURCE_DIR}/tools/process.bat $<TARGET_FILE:myLib> myLib.txt
    DEPENDS myLib
    WORKING_DIRECTORY $<TARGET_FILE_DIR:myLib>
    VERBATIM)

But then I get:

add_custom_command called with OUTPUT containing a "<".  This character is not allowed.

How am I supposed to get per-configuration custom command outputs?

2

For some cases, you can use the variable CMAKE_CFG_INTDIR containing a buildtool-specific string which expands to the active configuration at build time.

For more complex cases, sometimes you have to bite the bullet and create a separate custom command for each configuration and then “assign” it to the appropriate configuration by other means (such as a config-conditional genex in the list of sources, or creating a custom target for each config, or …)

1 Like
3

Thank you, that worked for me!

I also saw that OUTPUT is getting support for generator expressions in 3.20, so that’s cool!

4

That’s not just “cool”, that’s absolutely fantastic!, at least in my view. Thanks for letting me know. Oh, the number of workarounds I had to write around that one…

Now, I can just hope I will be given the time to reverse them all :slight_smile: