# Design of building OpenTelemetry C++ SDK and exporters as DLL **NOTE**: the current build produces a single DLL which includes API, SDK and exporters. This **MAY** change in future. OpenTelemetry C++ can be built into single DLL named opentelemetry_cpp.dll on Windows, with CMake flag `OPENTELEMETRY_BUILD_DLL` set to `ON`. To instrument an application based on the DLL, please define macro `OPENTELEMETRY_BUILD_IMPORT_DLL` before including any OpenTelemetry API header files in the application source files.