diff --git a/VERSION.TXT b/VERSION.TXT
index 65d2e34..b6e6f76 100644
--- a/VERSION.TXT
+++ b/VERSION.TXT
@@ -1,5 +1,10 @@
 			           NORM Version History
 
+Version 1.5.8
+=============
+    - Corrections to eliminate compiler warnings and suport kfreebsd builds
+      (Thanks to Luca Buccassi)
+
 Version 1.5.7
 =============
     - Fixed issue with NormSession::SenderRemoveAckingNode() method where
diff --git a/include/normApi.h b/include/normApi.h
index e0ecce2..3beaae0 100644
--- a/include/normApi.h
+++ b/include/normApi.h
@@ -33,7 +33,11 @@ typedef int32_t INT32;
 typedef uint8_t UINT8;
 typedef uint16_t UINT16;
 typedef uint32_t UINT32;
-#define NORM_API_LINKAGE 
+#if (defined __GNUC__ && __GNUC__ >= 4)
+#define NORM_API_LINKAGE __attribute__ ((visibility ("default")))
+#else
+#define NORM_API_LINKAGE
+#endif
 #endif // if/else WIN32/UNIX
 
 ////////////////////////////////////////////////////////////
@@ -324,6 +328,8 @@ void NormSetTxOnly(NormSessionHandle sessionHandle,
                    bool              txOnly,
                    bool              connectToSessionAddress DEFAULT(false));
 
+NORM_API_LINKAGE
+void NormSetId(NormSessionHandle sessionHandle, NormNodeId normId);
 
 // This does not affect the rx_socket binding if already bound (sender or receiver already started)
 // (i.e., just affects where NORM packets are sent)
diff --git a/include/normVersion.h b/include/normVersion.h
index c558a2e..4e969fa 100644
--- a/include/normVersion.h
+++ b/include/normVersion.h
@@ -36,6 +36,6 @@
  
 #ifndef _NORM_VERSION
 #define _NORM_VERSION
-#define VERSION "1.5.7"
+#define VERSION "1.5.8"
 #endif // _NORM_VERSION
         
diff --git a/src/common/normFile.cpp b/src/common/normFile.cpp
index 2ba3acf..535d8b9 100644
--- a/src/common/normFile.cpp
+++ b/src/common/normFile.cpp
@@ -185,10 +185,16 @@ void NormFile::Unlock()
 {
 #ifndef WIN32
 #ifdef HAVE_FLOCK
-    flock(fd, LOCK_UN);
+    if (0 != flock(fd, LOCK_UN))
+    {
+        PLOG(PL_ERROR, "NormFile::Unlock() flock() error: %s\n", GetErrorString());
+    }
 #else
 #ifdef HAVE_LOCKF
-    lockf(fd, F_ULOCK, 0);
+    if (0 != lockf(fd, F_ULOCK, 0))
+    {
+        PLOG(PL_ERROR, "NormFile::Unlock() lockf() error: %s\n", GetErrorString());
+    }
 #endif // HAVE_LOCKF
 #endif // if/elseHAVE_FLOCK
     fchmod(fd, 0640);
diff --git a/wscript b/wscript
index ebcaf4a..8428899 100644
--- a/wscript
+++ b/wscript
@@ -64,6 +64,10 @@ def configure(ctx):
     if system == 'windows':
         ctx.env.DEFINES_BUILD_NORM += ['NORM_USE_DLL']
 
+    if ctx.env.COMPILER_CXX == 'g++' or ctx.env.COMPILER_CXX == 'clang++':
+        ctx.env.CFLAGS += ['-fvisibility=hidden']
+        ctx.env.CXXFLAGS += ['-fvisibility=hidden']
+
 def build(ctx):
     ctx.recurse('protolib')