diff --git a/common/Makefile.am b/common/Makefile.am
index 905a2b2..d805809 100644
--- a/common/Makefile.am
+++ b/common/Makefile.am
@@ -1,4 +1,4 @@
-SUBDIRS =
+SUBDIRS = os
 
 if INCLUDED_ZLIB
 SUBDIRS += zlib
diff --git a/common/common-config.win.h b/common/common-config.win.h
new file mode 100644
index 0000000..e68d372
--- /dev/null
+++ b/common/common-config.win.h
@@ -0,0 +1,4 @@
+/* common-config.win.h - Platform-specific definitions for Windows */
+
+#define HAVE_VSNPRINTF 1
+#define vsnprintf _vsnprintf
diff --git a/common/configure.ac b/common/configure.ac
index fc2f8bf..fabde36 100644
--- a/common/configure.ac
+++ b/common/configure.ac
@@ -87,6 +87,7 @@
 AC_CHECK_HEADERS([sys/select.h])
 
 AC_OUTPUT([Makefile
+	   os/Makefile
 	   rdr/Makefile
 	   network/Makefile
 	   Xregion/Makefile
diff --git a/common/os/Makefile.am b/common/os/Makefile.am
new file mode 100644
index 0000000..23e4dfb
--- /dev/null
+++ b/common/os/Makefile.am
@@ -0,0 +1,5 @@
+noinst_LTLIBRARIES = libos.la
+
+HDRS = print.h
+
+libos_la_SOURCES = $(HDRS) print.c
diff --git a/common/os/print.c b/common/os/print.c
new file mode 100644
index 0000000..a38ea2f
--- /dev/null
+++ b/common/os/print.c
@@ -0,0 +1,58 @@
+/* Copyright (C) 2008 TightVNC Team.  All Rights Reserved.
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+
+#ifdef HAVE_COMMON_CONFIG_H
+#include <common-config.h>
+#endif
+
+#include <os/print.h>
+#include <stdarg.h>
+
+#ifndef HAVE_VSNPRINTF
+int vsnprintf(char *str, size_t n, const char *format, va_list ap) {
+	static FILE *fp = NULL;
+	va_list ap_new;
+	int len, written;
+
+	if (n < 1)
+		return 0;
+
+	str[0] = '\0';
+	if (fp == NULL) {
+		fp = fopen("/dev/null","w");
+		if (fp == NULL)
+			return 0;
+	}
+
+	va_copy(ap_new, ap);
+	len = vfprintf(fp, format, ap_new);
+	va_end(ap_new);
+
+	if (len <= 0)
+		return 0;
+
+	CharArray s(len+1);
+	vsprintf(s.buf, format, ap);
+
+	written = (len < (n - 1)) ? len : (n - 1);
+	memcpy(str, s.buf, written);
+	str[written] = '\0';
+	return len;
+}
+#endif /* HAVE_VSNPRINTF */
+
diff --git a/common/os/print.h b/common/os/print.h
new file mode 100644
index 0000000..471002c
--- /dev/null
+++ b/common/os/print.h
@@ -0,0 +1,37 @@
+/* Copyright (C) 2008 TightVNC Team.  All Rights Reserved.
+ *
+ * This is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This software is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this software; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ * USA.
+ */
+
+#ifndef OS_PRINT_H
+#define OS_PRINT_H
+
+#ifdef HAVE_COMMON_CONFIG_H
+#include <common-config.h>
+#endif
+
+#ifdef WIN32
+#include <common-config.win32.h>
+#endif
+
+#include <stdarg.h>
+#include <sys/types.h>
+
+#ifndef HAVE_VSNPRINTF
+int vsnprintf(char *str, size_t n, const char *format, va_list ap);
+#endif
+
+#endif /* OS_PRINT_H */
diff --git a/common/rfb/Logger.cxx b/common/rfb/Logger.cxx
index 8c90906..451cee2 100644
--- a/common/rfb/Logger.cxx
+++ b/common/rfb/Logger.cxx
@@ -18,64 +18,20 @@
 
 // -=- Logger.cxx - support for the Logger and LogWriter classes
 
-#ifdef HAVE_COMMON_CONFIG_H
-#include <common-config.h>
-#endif
-
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>
 #ifdef WIN32
 #define strcasecmp _stricmp
-#define vsnprintf _vsnprintf
-#define HAVE_VSNPRINTF
 #endif
 
+#include <os/print.h>
 #include <rfb/Logger.h>
 #include <rfb/LogWriter.h>
 #include <rfb/util.h>
-#include <rfb/Threading.h>
 
 using namespace rfb;
 
-#ifndef HAVE_VSNPRINTF
-#ifdef __RFB_THREADING_IMPL
-static Mutex fpLock;
-#endif
-static FILE* fp = 0;
-int vsnprintf(char *str, size_t n, const char *format, va_list ap)
-{
-  va_list ap_new;
-  int len, written;
-
-  str[0] = 0;
-  if (!fp) {
-    // Safely create a FILE* for /dev/null if there isn't already one
-#ifdef __RFB_THREADING_IMPL
-    Lock l(fpLock);
-#endif
-    if (!fp)
-      fp = fopen("/dev/null","w");
-    if (!fp) return 0;
-  }
-
-  va_copy(ap_new, ap);
-  len = vfprintf(fp, format, ap_new);
-  va_end(ap_new);
-
-  if (len <= 0) return 0;
-
-  CharArray s(len+1);
-  vsprintf(s.buf, format, ap);
-
-  written = __rfbmin(len, (int)n-1);
-  memcpy(str, s.buf, written);
-  str[written] = '\0';
-  return len;
-}
-#endif
-
-
 Logger* Logger::loggers = 0;
 
 Logger::Logger(const char* name) : registered(false), m_name(name), m_next(0) {