The normal and most flexible way to add a CppMicroServices bundle to
an application is to compile it into a shared library using the
BundleContext::InstallBundles() function at runtime.
However, bundles can be linked statically to your application or shared library. This makes the deployment of your application less error-prone and in the case of a complete static build, also minimizes its binary size and start-up time. However, in order to add new functionality to your application, you must rebuild and redistribute it.
Creating Static Bundles¶
Static bundles are written just like shared bundles - there are no differences in the usage of the CppMicroServices API or the provided preprocessor macros.
Using Static Bundles¶
Static bundles can be used (imported) in shared or other static
libraries, or in the executable itself. For every static bundle you would
like to import, you need to add a call to
CPPMICROSERVICES_IMPORT_BUNDLE or to
CPPMICROSERVICES_INITIALIZE_STATIC_BUNDLE (if the bundle does not
provide an activator) in the source code of the importing library.
While you can link static bundles to other static bundles, you will still need to import all of the static bundles into the final executable to ensure proper initialization.
The two main usage scenarios- using a shared or static CppMicroServices library- are explained in the sections below.
Using a Static CppMicroServices Library¶
The CppMicroServices library can be built as a static library. In that case, creating shared bundles is not supported. If you create shared bundles that link a static version of the CppMicroServices library, the runtime behavior is undefined.
In this usage scenario, every bundle will be statically build and linked to an executable:
#include "cppmicroservices/BundleImport.h" #ifndef US_BUILD_SHARED_LIBS CPPMICROSERVICES_INITIALIZE_STATIC_BUNDLE(system_bundle) CPPMICROSERVICES_IMPORT_BUNDLE(MyStaticBundle2) CPPMICROSERVICES_INITIALIZE_STATIC_BUNDLE(main) #endif
Note that the first
CPPMICROSERVICES_IMPORT_BUNDLE call imports the
static CppMicroServices library. Next, the
MyStaticBundle2 bundle is
imported and finally, the executable itself is initialized (this is
necessary if the executable itself is a C++ Micro Services bundle).