How can I get the objlist from the generator-expressions $<TARGET_OBJECTS:objLib>

Usage
1

I want to get the obj file location and use it for the depends in the add_custom_command.
The question is:
1.how to process the $<TARGET_OBJECTS:objLib> to get specific location,like this
$<TARGET_OBJECTS:objLib> is the list of a/a.o b/b.o c/c.o,and I need to get the a/a.o
2.Is there any else way to do this?

thanks

2

Since CMake 3.15 (https://cmake.org/cmake/help/v3.15/manual/cmake-generator-expressions.7.html#string-transformations), you can use $<FILTER:list,INCLUDE|EXCLUDE,regex> to filter items in or out of a generator expression. For instance:

$<FILTER:$<TARGET_OBJECTS:objLib>,INCLUDE,a/>

I hope this helps.

3

For example
aaaa/dddd/ffff/a.o cccc/hhhhh/llll/b.o
But I do not know the directory name,and I just know the a.o,how can I get the whole aaaa/dddd/ffff/a.o

4

I tried this
DEPENDS $<FILTER:$<TARGET_OBJECTS:objLib>,INCLUDE,root/>

and got the error
$<FILTER:$<TARGET_OBJECTS:objLib>,INCLUDE,root/>

Expression did not evaluate to a known generator expression

5

Which version of CMake are you using?

6

3.14

7

Sorry,I have just saw you said the version is CMake 3.15.I will try.
thanks

8

Now,I got the cmake generate ok.But how to deal with the below case
For example
aaaa/dddd/ffff/a.o cccc/hhhhh/llll/b.o
But I do not know the directory name,and I just know the a.o,how can I get the whole aaaa/dddd/ffff/a.o

9

I guess something like

$<FILTER:$<TARGET_OBJECTS:objLib>,INCLUDE,/a.o>

would work.

10

It does work.
Thank you very much.

11

Hi I have a similar problem but i have multiple directories linked to a specific target and I need to get all the object files from all the related directories. So I have A/aaa_a/testing/a_a.o , A/aaa_b/testing/a_b.o, A/aaa_c/testing/a_c.o, A/aaa_d/testing/a_d.o and i need all the a_a.o,a_b.o,a_c.o,a_d.o using the generator expressions $<TARGET_OBJECTS:A>, please help!