2 files changed, 73 insertions, 0 deletions
diff --git a/example/dynamic_load/CMakeLists.txt b/example/dynamic_load/CMakeLists.txt
new file mode 100644
index 0000000..1413a4b
--- /dev/null
+++ b/example/dynamic_load/CMakeLists.txt
@@ -0,0 +1,4 @@
+if (BUILD_DYNAMIC_LOADING AND BUILD_SHARED_LIBS)
+  add_executable(dynamic_load-example dynamic_load-example.cpp)
+  target_link_libraries(dynamic_load-example opentracing)
+endif()
diff --git a/example/dynamic_load/dynamic_load-example.cpp b/example/dynamic_load/dynamic_load-example.cpp
new file mode 100644
index 0000000..f49996f
--- /dev/null
+++ b/example/dynamic_load/dynamic_load-example.cpp
@@ -0,0 +1,69 @@
+// Demonstrates how to load a tracer library in at runtime and how to use it
+// to construct spans. To run it using the mocktracer, invoke with
+//
+//     TRACER_CONFIG=`mktemp`
+//     echo '{ "output_file": "/dev/stdout" }' > $TRACER_CONFIG
+//     dynamic_load-example /path/to/libopentracing_mocktracer.so $TRACER_CONFIG
+
+#include <opentracing/dynamic_load.h>
+#include <cassert>
+#include <cerrno>
+#include <fstream>
+#include <iostream>
+#include <iterator>
+#include <string>
+
+#ifdef _MSC_VER
+#pragma warning(push)
+#pragma warning(disable : 4996)
+#endif
+
+int main(int argc, char* argv[]) {
+  if (argc != 3) {
+    std::cerr << "Usage: <tracer_library> <tracer_config_file>\n";
+    return -1;
+  }
+
+  // Load the tracer library.
+  std::string error_message;
+  auto handle_maybe =
+      opentracing::DynamicallyLoadTracingLibrary(argv[1], error_message);
+  if (!handle_maybe) {
+    std::cerr << "Failed to load tracer library " << error_message << "\n";
+    return -1;
+  }
+
+  // Read in the tracer's configuration.
+  std::ifstream istream{argv[2]};
+  if (!istream.good()) {
+    std::cerr << "Failed to open tracer config file " << argv[2] << ": "
+              << std::strerror(errno) << "\n";
+    return -1;
+  }
+  std::string tracer_config{std::istreambuf_iterator<char>{istream},
+                            std::istreambuf_iterator<char>{}};
+
+  // Construct a tracer.
+  auto& tracer_factory = handle_maybe->tracer_factory();
+  auto tracer_maybe =
+      tracer_factory.MakeTracer(tracer_config.c_str(), error_message);
+  if (!tracer_maybe) {
+    std::cerr << "Failed to create tracer " << error_message << "\n";
+    return -1;
+  }
+  auto& tracer = *tracer_maybe;
+
+  // Use the tracer to create some spans.
+  {
+    auto span_a = tracer->StartSpan("A");
+    assert(span_a != nullptr);
+    span_a->SetTag("abc", 123);
+    auto span_b =
+        tracer->StartSpan("B", {opentracing::ChildOf(&span_a->context())});
+    assert(span_b != nullptr);
+    span_b->SetTag("xyz", 987);
+  }
+
+  tracer->Close();
+  return 0;
+}