CODEWITHSUNDEEP
cmake
Fabian Keßler
Fabian Keßler

Reputation: 682

Make FetchContent compatible with find_package

I try to add all dependencies needed for my project to compile over CMake. This should reduce the overhead others will have when they want to compile the project for the first time.

To achive this, I tried to use FetchContent. So far so good, when I link the generated targets its not a problem at all. But now I have a library depending itself on annother lib which isn't included as submodule. The lib tries to find the dependency over find_package. How can I get find_package to find the library?

What I tried so far:

Here a minimal snipped of my CMake code of the later:

cmake_minimum_required(VERSION 3.14)

find_package(ZLIB)
if (NOT ZLIB_FOUND)
    FetchContent_Declare(zlib_fetch
        GIT_REPOSITORY https://github.com/madler/zlib.git
        GIT_TAG cacf7f1d4e3d44d871b605da3b647f07d718623f
        )
    FetchContent_MakeAvailable(zlib_fetch)
    set(ZLIB_DIR ${zlib_fetch_BINARY_DIR})
    message(${zlib_fetch_BINARY_DIR})
#simulates the call in the other library:
    find_package(ZLIB REQUIRED) 
endif (NOT ZLIB_FOUND)

Upvotes: 14

Views: 8148

Answers (1)

Eyjafl
Eyjafl

Reputation: 2195

Starting with CMake 3.24, FetchContent_Declare has OVERRIDE_FIND_PACKAGE option which, when specified, makes CMake redirect the subsequent calls to find_package(<name>) so that FetchContent_Declare(<name> ...) satisfies the dependency (note that <name> must stay the same here).

Upvotes: 14

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