[CMake] print a message during a specific build target

[Christopher Sean Morrison]

Thanks, that worked for printing a message during our “check” target.  Makes sense for “if (TARGET…)” to truthfully enter if that target name exists.  What threw me off, I think, was having "TARGET test” not actually pass and misunderstanding the docs that this would embed logic in the generator output.

I ended up adding COMMAND ${CMAKE_COMMAND} -E echo “…” lines to the add_custom_target() and that did the trick for my “check” target.  Getting similar behavior for the “test" target seems to be impossible, though.

I even tried to trick ctest by creating a test that printed a message but failed.  I could create a custom target that only printed a message and ran ‘false’ to give an error; and I could create another cmake target that ran ctest with —output-on-failure to see the message — and that worked just fine for running that target via cmake.  However, every which way I tried to invoke that target via add_test seemed to only produce an infinite loop during “make test” or ctest.

What I ended up doing was punting on displaying the fancy message and just added a test whose test name was a very shortened form of the message intended (via add_test(NAME “NOTE\\ important\\ message\\ here”…).  Made the test still run the ‘false’ message target too (via COMMAND cmake …), so it ends up in the testing log during make test and conveniently pauses for 3-4 seconds on just that one test (apparently the overhead on our build system to simply invoke cmake).

In all, it’s working, but hopefully this info might be useful to any archive searcher hitting a similar problem… at least until http://public.kitware.com/Bug/view.php?id=8438 is addressed... 

Cheers!
Sean



On Nov 24, 2015, at 7:44 AM, Parag Chandra <parag at ionicsecurity.com> wrote:

> The if() statements are executed when CMake runs, because you’re basically adding logic to the “meta-build” process that generates your build system; not the build system itself. Maybe you can use “add_custom_target” to create targets which do nothing but print the desired message, and then use “add_dependencies” to tie these targets back to your original ones? So something like:
> 
> add_custom_target(“test_print” …)
> add_dependencies(test test_print)
> 
> 
> 
> 
> Parag Chandra
> Senior Software Engineer, Mobile Team
> Mobile: +1.919.824.1410
> 
> <https://ionic.com> 
> 
> Ionic Security Inc.
> 1170 Peachtree St. NE STE 400, Atlanta, GA 30309
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> On 11/24/15, 12:04 AM, "CMake on behalf of Christopher Sean Morrison" <cmake-bounces at cmake.org on behalf of brlcad at mac.com> wrote:
> 
>> 
>> Hi,
>> 
>> I’m trying to print a message for a particular build target and am a bit stuck.  I found that the IF statement has a TARGET keyword that should truthfully match for a particular build target, but it doesn’t seem to be working at least the way I’m trying to use it and would expect it to work.  Snippet in question in a top-level CMakeLists.txt file looks like this:
>> 
>> if (TARGET check)
>> message(“special note about CHECK target…”)
>> elseif (TARGET test)
>> message(“different note about TEST target…”)
>> endif (TARGET check)
>> 
>> Now what happens is that the CHECK message is printed … during cmake(!).  What I’m trying to achieve is only have those messages printed during≈ “make check” and “make test”, etc.  Ideally, I want to be able to inject a message before any target actions are taken and possibly after.
>> 
>> I see in the docs that I can set COMMENT during add_custom_target(check …) and that should print my message before any target actions, but how can I get a similar message printed during ‘test’ or ‘all’ or some other implicit target?  Is there a better or more general way?  Thanks for your assistance.
>> 
>> Cheers!
>> Sean
>> 
>> -- 
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