1 files changed, 8 insertions, 0 deletions
diff --git a/libs/pbd/pthread_utils.cc b/libs/pbd/pthread_utils.cc
index 96cf99716f..91d93ec4f8 100644
--- a/libs/pbd/pthread_utils.cc
+++ b/libs/pbd/pthread_utils.cc
@@ -28,6 +28,14 @@
 #include <fst.h>
 #endif
 
+#ifdef COMPILER_MSVC
+DECLARE_DEFAULT_COMPARISONS(pthread_t)  // Needed for 'DECLARE_DEFAULT_COMPARISONS'. Objects in an STL container can be
+                                        // searched and sorted. Thus, when instantiating the container, MSVC complains
+                                        // if the type of object being contained has no appropriate comparison operators
+                                        // defined (specifically, if operators '<' and '==' are undefined). This seems
+                                        // to be the case with ptw32 'pthread_t' which is a simple struct.
+#endif
+
 using namespace std;
 
 typedef std::list<pthread_t> ThreadMap;