conan.tools.CppInfo

The CppInfo class represents the basic C++ usage information of a given package, like the includedirs, libdirs, library names, etc. It is the information that the consumers of the package need in order to be able to find the headers and link correctly with the libraries.

The self.cpp_info object in the package_info() is a CppInfo object, so in most cases it will not be necessary to explicitly instantiate it, and using it as explained in the package_info() section would be enough.

This section describes the other, advanced uses cases of the CppInfo.

Aggregating information in custom generators

Warning

This feature is experimental and subject to breaking changes. See the Conan stability section for more information.

Some generators, like the built-in NMakeDeps, contains the equivalent to this code, that collapses all information from all dependencies into one single CppInfo object that aggregates all the information

from conan.tools import CppInfo
...
def generate(self):
    aggregated_cpp_info = CppInfo(self)
    deps = self.dependencies.host.topological_sort
    deps = [dep for dep in reversed(deps.values())]
    for dep in deps:
        # We don't want independent components management, so we collapse
        # the "dep" components into one CppInfo called "dep_cppinfo"
        dep_cppinfo = dep.cpp_info.aggregated_components()
        # Then we merge and aggregate this dependency "dep" into the final result
        aggregated_cpp_info.merge(dep_cppinfo)
    aggregated_cpp_info.includedirs  # All include dirs from all deps, all components
    aggregated_cpp_info.libs  # All library names from all deps, all components
    aggregated_cpp_info.system_libs # All system-libs from all deps
    ....
    # Creates a file with this information that the build system will use

This aggregation could be useful in cases where the build system cannot easily use independent dependencies or components. For example NMake or Autotools mechanism to provide dependencies information would be via LIBS, CXXFLAGS and similar variables. These variables are global, so passing all the information from all dependencies is the only possibility.

The public documented interface (besides the defined one in the package_info()) is:

• CppInfo(conanfile): Constructor. Receives a conanfile as argument, typically self

• aggregated_components(): return a new CppInfo object resulting from the aggregation of all the components

• get_sorted_components(): Get the ordered components of a package, prioritizing those with fewer dependencies within the same package. Returns an OrderedDict of sorted components in the format {component_name: component}.

• merge(other_cppinfo: CppInfo): modifies the current CppInfo object, updating it with the information of the parameter other_cppinfo, allowing to aggregate information from multiple dependencies.