CMake (with dependencies)¶

If your project uses external packages (i.e. has command find_package(Foo)) you need to patch it first so these packages can be found in the Hunter root directory instead of the standard one:

hunter_add_package(Foo)
find_package(Foo)

Note

Patching sources (hunter-packages)

Conflict¶

Without the hunter_add_package(Foo) call one package will be found in the standard location and another one in the Hunter root directory. The found packages may conflict with each other.

Consider the next example: Project Roo is not aware about Hunter custom locations. It’s just using regular find_package:

# Roo/CMakeLists.txt

find_package(ZLIB)

Project Bar depends on ZLIB and Roo. Both packages are downloaded by hunter_add_package commands:

# Bar/CMakeLists.txt

hunter_add_package(Roo)
find_package(Roo)

hunter_add_package(ZLIB)
find_package(ZLIB)

Fix¶

To fix this issue you need to patch project Roo so it will use ZLIB from Hunter. In terms of CMake code it means adding HunterGate and hunter_add_package (see First Step):

# Roo/CMakeLists.txt

include("cmake/HunterGate.cmake")
HunterGate(...)
hunter_add_package(ZLIB)
find_package(ZLIB CONFIG REQUIRED)

../../_images/package-conflict-resolved.png

Note that now the main project Bar and the hunter dependency Roo contain a HunterGate command. The URL and SHA1 of the HunterGate command my not match. In this case the URL and SHA1 of the main project Bar are used for both HunterGate commands. The user does not need to manage them manually. The same is true for sub-projects added by add_subdirectory calls.