cmake

This is the reference page for cmake generator. Go to Integrations/CMake if you want to learn how to integrate your project or recipes with CMake.

It generates a file named conanbuildinfo.cmake and declares some variables and methods

Variables in conanbuildinfo.cmake

  • Package declared vars

For each requirement conanbuildinfo.cmake file declares the following variables. XXX is the name of the require in uppercase. e.k “ZLIB” for zlib/1.2.8@lasote/stable requirement:

NAME VALUE
CONAN_XXX_ROOT Abs path to root package folder.
CONAN_INCLUDE_DIRS_XXX Header’s folders
CONAN_LIB_DIRS_XXX Library folders (default {CONAN_XXX_ROOT}/lib)
CONAN_BIN_DIRS_XXX Binary folders (default {CONAN_XXX_ROOT}/bin)
CONAN_SRC_DIRS_XXX Sources folders
CONAN_LIBS_XXX Library names to link
CONAN_DEFINES_XXX Library defines
CONAN_COMPILE_DEFINITIONS_XXX Compile definitions
CONAN_CXX_FLAGS_XXX CXX flags
CONAN_SHARED_LINK_FLAGS_XXX Shared link flags
CONAN_C_FLAGS_XXX C flags
  • Global declared vars

Conan also declares some global variables with the aggregated values of all our requirements. The values are ordered in the right order according to the dependency tree.

NAME VALUE
CONAN_INCLUDE_DIRS Aggregated header’s folders
CONAN_LIB_DIRS Aggregated library folders
CONAN_BIN_DIRS Aggregated binary folders
CONAN_SRC_DIRS Aggregated sources folders
CONAN_LIBS Aggregated library names to link
CONAN_DEFINES Aggregated library defines
CONAN_COMPILE_DEFINITIONS Aggregated compile definitions
CONAN_CXX_FLAGS Aggregated CXX flags
CONAN_SHARED_LINK_FLAGS Aggregated Shared link flags
CONAN_C_FLAGS Aggregated C flags
  • Variables from user_info

If any of the requirements is filling the user_info object in the package_info method a set of variables will be declared following this naming:

NAME VALUE
CONAN_USER_XXXX_YYYY User declared value

XXXX is the name of the requirement in uppercase and YYYY the variable name, e.g.:

class MyLibConan(ConanFile):
    name = "MyLib"
    version = "1.6.0"

    # ...

    def package_info(self):
        self.user_info.var1 = 2

When other library requires MyLib and uses the cmake generator:

conanbuildinfo.cmake:

# ...
set(CONAN_USER_MYLIB_var1 "2")

Methods available in conanbuildinfo.cmake

conan_basic_setup

Setup all the CMake vars according to our settings, by default with the global approach (no targets).

parameters: You can combine several parameters to the conan_basic_setup macro, e.g., conan_basic_setup(TARGETS KEEP_RPATHS)

  • TARGETS: Setup all the CMake vars by target (only CMake > 3.1.2)
  • NO_OUTPUT_DIRS: Do not adjust the output directories
  • KEEP_RPATHS: Do not adjust the CMAKE_SKIP_RPATH variable in OSX

Other optional methods and variables

There are other methods automatically called by conan_basic_setup() but you can use them directly:

NAME DESCRIPTION
conan_check_compiler()

Checks that your compiler matches the one declared in settings

Can be disabled setting CONAN_DISABLE_CHECK_COMPILER CMake var
conan_output_dirs_setup() Adjust the bin/ and lib/ output directories
conan_set_find_library_paths() Set CMAKE_INCLUDE_PATH and CMAKE_INCLUDE_PATH
conan_global_flags() Set include_directories, link_directories, link_directories, flags
conan_define_targets() Define the targets (target flags instead of global flags)
conan_set_rpath() Set CMAKE_SKIP_RPATH=1 if APPLE
conan_set_vs_runtime() Adjust the runtime flags (/MD /MDd /MT /MTd)
conan_set_libcxx(TARGETS) Adjust the standard library flags (libstdc++, libc++, libstdc++11)
conan_set_find_paths() Adjust CMAKE_MODULE_PATH and CMAKE_PREFIX_PATH
CONAN_CMAKE_SILENT_OUTPUT Silences the Conan message output

Targets generated by conanbuildinfo.cmake

If you use conan_basic_setup(TARGETS), then some cmake targets will be generated (this only works for CMake > 3.1.2)

These targets are:

  • A CONAN_PKG::PkgName target per package in the dependency graph. This is an IMPORTED INTERFACE target. IMPORTED because it is external, a pre-compiled library. INTERFACE, because it doesn’t necessarily match a library, it could be a header-only library, or the package could even contain several libraries. It contains all the properties (include paths, compile flags, etc) that are defined in the package_info() method of the package.
  • Inside each package a CONAN_LIB::PkgName_LibName target will be generated for each library. Its type is IMPORTED UNKNOWN, its main purpose is to provide a correct link order. Their only properties are the location and the dependencies
  • A CONAN_PKG depends on every CONAN_LIB that belongs to it, and to its direct public dependencies (i.e. other CONAN_PKG targets from its requires)
  • Each CONAN_LIB depends on the direct public dependencies CONAN_PKG targets of its container package. This guarantees correct link order.