Find Packages

If a FindXXX.cmake file for the library you are packaging is already available, it should work automatically.

Variables CMAKE_INCLUDE_PATH and CMAKE_LIBRARY_PATH are set with the requirements paths. The CMake find_library function will be able to locate the libraries in the package’s folders.

So, you can use find_package normally:

project(MyHello)
cmake_minimum_required(VERSION 2.8.12)

include(conanbuildinfo.cmake)
conan_basic_setup()

find_package("ZLIB")

if(ZLIB_FOUND)
    add_executable(enough enough.c)
    include_directories(${ZLIB_INCLUDE_DIRS})
    target_link_libraries(enough ${ZLIB_LIBRARIES})
else()
    message(FATAL_ERROR "Zlib not found")
endif()

In addition to automatic find_package support, CMAKE_MODULE_PATH variable is set with the requirements root package paths. You can override the default behavior of any find_package() by creating a findXXX.cmake file in your package.

Creating a custom FindXXX.cmake file

Sometimes the “official” CMake FindXXX.cmake scripts are not ready to find our libraries (unsupported library names for specific settings, fixed installation directories like C:\OpenSSL, etc.) Or maybe there is no “official” CMake script for our library.

In these cases we can provide a custom FindXXX.cmake file in our Conan packages.

1. Create a file named FindXXX.cmake and save it in your Conan package root folder, where XXX is the name of the library that we will use in the find_package CMake function. For example, we create a FindZLIB.cmake and use find_package(ZLIB). We recommend copying the original FindXXX.cmake file from Kitware (folder Modules/FindXXX.cmake), if available, and modifying it to help find our library files, but it depends a lot; maybe you are interested in creating a new one.

If it’s not provided, you can create a basic one. Take a look at this example with the ZLIB library:

FindZLIB.cmake

find_path(ZLIB_INCLUDE_DIR NAMES zlib.h PATHS ${CONAN_INCLUDE_DIRS_ZLIB})
find_library(ZLIB_LIBRARY NAMES ${CONAN_LIBS_ZLIB} PATHS ${CONAN_LIB_DIRS_ZLIB})

set(ZLIB_FOUND TRUE)
set(ZLIB_INCLUDE_DIRS ${ZLIB_INCLUDE_DIR})
set(ZLIB_LIBRARIES ${ZLIB_LIBRARY})
mark_as_advanced(ZLIB_LIBRARY ZLIB_INCLUDE_DIR)

In the first line we find the path where the headers should be found. We suggest the CONAN_INCLUDE_DIRS_XXX. Then repeat for the library names with CONAN_LIBS_XXX and the paths where the libs are CONAN_LIB_DIRS_XXX.

  1. In your conanfile.py file add the FindXXX.cmake to the exports_sources field:

class HelloConan(ConanFile):
    name = "hello"
    version = "0.1"
    ...
    exports_sources = ["FindXXX.cmake"]

  1. In the package method, copy the FindXXX.cmake file to the root:

class HelloConan(ConanFile):
    name = "hello"
    version = "0.1"
    ...
    exports_sources = ["FindXXX.cmake"]


    def package(self):
        ...
        self.copy("FindXXX.cmake", ".", ".")