diff --git a/builds/msvc/c_local_lat/c_local_lat.vcproj b/builds/msvc/c_local_lat/c_local_lat.vcproj
index 5f7cdb22..a8d9a8df 100644
--- a/builds/msvc/c_local_lat/c_local_lat.vcproj
+++ b/builds/msvc/c_local_lat/c_local_lat.vcproj
@@ -165,10 +165,6 @@
 			Filter="cpp;c;cc;cxx;def;odl;idl;hpj;bat;asm;asmx"
 			UniqueIdentifier="{4FC737F1-C7A5-4376-A066-2A32D752A2FF}"
 			>
-			<File
-				RelativePath="..\..\..\perf\helpers.cpp"
-				>
-			</File>
 			<File
 				RelativePath="..\..\..\perf\local_lat.cpp"
 				>
diff --git a/builds/msvc/c_local_thr/c_local_thr.vcproj b/builds/msvc/c_local_thr/c_local_thr.vcproj
index 5d5b9b15..38425cce 100644
--- a/builds/msvc/c_local_thr/c_local_thr.vcproj
+++ b/builds/msvc/c_local_thr/c_local_thr.vcproj
@@ -165,10 +165,6 @@
 			Filter="cpp;c;cc;cxx;def;odl;idl;hpj;bat;asm;asmx"
 			UniqueIdentifier="{4FC737F1-C7A5-4376-A066-2A32D752A2FF}"
 			>
-			<File
-				RelativePath="..\..\..\perf\helpers.cpp"
-				>
-			</File>
 			<File
 				RelativePath="..\..\..\perf\local_thr.cpp"
 				>
diff --git a/builds/msvc/c_remote_lat/c_remote_lat.vcproj b/builds/msvc/c_remote_lat/c_remote_lat.vcproj
index 81e56a05..5bce7e97 100644
--- a/builds/msvc/c_remote_lat/c_remote_lat.vcproj
+++ b/builds/msvc/c_remote_lat/c_remote_lat.vcproj
@@ -165,10 +165,6 @@
 			Filter="cpp;c;cc;cxx;def;odl;idl;hpj;bat;asm;asmx"
 			UniqueIdentifier="{4FC737F1-C7A5-4376-A066-2A32D752A2FF}"
 			>
-			<File
-				RelativePath="..\..\..\perf\helpers.cpp"
-				>
-			</File>
 			<File
 				RelativePath="..\..\..\perf\remote_lat.cpp"
 				>
diff --git a/builds/msvc/c_remote_thr/c_remote_thr.vcproj b/builds/msvc/c_remote_thr/c_remote_thr.vcproj
index a1e465ae..10895491 100644
--- a/builds/msvc/c_remote_thr/c_remote_thr.vcproj
+++ b/builds/msvc/c_remote_thr/c_remote_thr.vcproj
@@ -165,10 +165,6 @@
 			Filter="cpp;c;cc;cxx;def;odl;idl;hpj;bat;asm;asmx"
 			UniqueIdentifier="{4FC737F1-C7A5-4376-A066-2A32D752A2FF}"
 			>
-			<File
-				RelativePath="..\..\..\perf\helpers.cpp"
-				>
-			</File>
 			<File
 				RelativePath="..\..\..\perf\remote_thr.cpp"
 				>
diff --git a/include/zmq_utils.h b/include/zmq_utils.h
index 50a50f90..5b78e10d 100644
--- a/include/zmq_utils.h
+++ b/include/zmq_utils.h
@@ -20,6 +20,10 @@
 #ifndef __ZMQ_UTILS_H_INCLUDED__
 #define __ZMQ_UTILS_H_INCLUDED__
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /*  Win32 needs special handling for DLL exports                              */
 #if defined _WIN32
 #   if defined DLL_EXPORT
@@ -46,4 +50,8 @@ ZMQ_EXPORT void zmq_sleep (int seconds_);
 
 #undef ZMQ_EXPORT
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif
diff --git a/src/zmq.cpp b/src/zmq.cpp
index 73a8d654..75e2e7fe 100644
--- a/src/zmq.cpp
+++ b/src/zmq.cpp
@@ -18,6 +18,7 @@
 */
 
 #include "../include/zmq.h"
+#include "../include/zmq_utils.h"
 
 #include <string.h>
 #include <errno.h>