ceph/src/jaegertracing/opentracing-cpp/include/opentracing/noop.h

   1 #ifndef OPENTRACING_NOOP_H
   2 #define OPENTRACING_NOOP_H
   3
   4 #include <opentracing/symbols.h>
   5 #include <opentracing/tracer.h>
   6 #include <opentracing/version.h>
   7 #include <memory>
   8
   9 namespace opentracing {
  10 BEGIN_OPENTRACING_ABI_NAMESPACE
  11 // A NoopTracer is a trivial, minimum overhead implementation of Tracer
  12 // for which all operations are no-ops.
  13 //
  14 // The primary use of this implementation is in libraries, such as RPC
  15 // frameworks, that make tracing an optional feature controlled by the
  16 // end user. A no-op implementation allows said libraries to use it
  17 // as the default Tracer and to write instrumentation that does
  18 // not need to keep checking if the tracer instance is nil.
  19 //
  20 // For the same reason, the NoopTracer is the default "global" tracer
  21 // (see Tracer::Global and Tracer::InitGlobal functions).
  22 //
  23 // WARNING: NoopTracer does not support baggage propagation.
  24 OPENTRACING_API std::shared_ptr<Tracer> MakeNoopTracer() noexcept;
  25 END_OPENTRACING_ABI_NAMESPACE
  26 }  // namespace opentracing
  27
  28 #endif  // OPENTRACING_NOOP_H