CODEWITHSUNDEEP
c++cmake
kubivan
kubivan

Reputation: 393

Cmake : how to append string to the variable via command line?

In my CMakeList.txt i can do the following thing: 

set(CMAKE_CXX_FLAGS "${CMAKE_C_FLAGS} -new -flags -here")

Is it possible to to the same thing via command line? Like: 

cmake.exe -DCMAKE_CXXFLAGS+= -new -flags

Upvotes: 26

Views: 47355

Answers (3)

jaques-sam
jaques-sam

Reputation: 2825

First of all, keep your hands off CMAKE_CXX_FLAGS! Use target_compile_options:

target_compile_options(<YOUR_TARGET> PRIVATE ${MY_FLAGS})

To expand other lists use list:

list(APPEND <YOUR_LIST> <ITEM_TO_ADD>)

Upvotes: 15

David K
David K

Reputation: 3132

If you don't like the command-line syntax specified by @Svalorzen, you could write a script that interprets its command-line arguments the way you like and converts them to something you can put on the cmake.exe command line. If portability is a concern, you could write the script in a language such as Perl (generally available on Unix-like platforms and can be installed on Windows).

If all this is going to buy you is an alternative solution to the problem you described, however, I would recommend just using the answer from @Svalorzen.

Upvotes: 0

Svalorzen
Svalorzen

Reputation: 5617

I'm not sure whether you can directly add options from the command line, but you can use an additional variable to store them and merge it at the end. Like the following:

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${MY_FLAGS}")

And then call cmake as following:

cmake -DMY_FLAGS="-new -flags"

Upvotes: 22

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