diff -Nur dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/apps/dcmconv.cc dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/apps/dcmconv.cc
--- dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/apps/dcmconv.cc	2017-07-14 17:41:11.000000000 +0200
+++ dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/apps/dcmconv.cc	2018-01-19 09:58:04.601534500 +0100
@@ -70,7 +70,7 @@
     } else {
       tagKey = dicent->getKey();
     }
-    dcmDataDict.unlock();
+    dcmDataDict.rdunlock();
     return tagKey;
   } else     /* tag name has format "gggg,eeee" */
   {
diff -Nur dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/apps/dcmdump.cc dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/apps/dcmdump.cc
--- dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/apps/dcmdump.cc	2017-07-14 17:41:11.000000000 +0200
+++ dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/apps/dcmdump.cc	2018-01-23 15:12:19.947386700 +0100
@@ -96,7 +96,7 @@
         } else {
             tagKey = dicent->getKey();
         }
-        dcmDataDict.unlock();
+        dcmDataDict.rdunlock();
         return tagKey;
     } else     /* tag name has format "gggg,eeee" */
     {
@@ -120,13 +120,13 @@
         const DcmDictEntry *dicent = globalDataDict.findEntry(tagName);
         if (dicent == NULL) {
             OFLOG_WARN(dcmdumpLogger, "unrecognized tag name: '" << tagName << "'");
-            dcmDataDict.unlock();
+            dcmDataDict.rdunlock();
             return OFFalse;
         } else {
             /* note for later */
             printTagKeys[printTagCount] = new DcmTagKey(dicent->getKey());
         }
-        dcmDataDict.unlock();
+        dcmDataDict.rdunlock();
     } else {
         /* tag name has format xxxx,xxxx */
         /* do not lookup in dictionary, tag could be private */
diff -Nur dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/apps/mdfdsman.cc dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/apps/mdfdsman.cc
--- dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/apps/mdfdsman.cc	2017-07-14 17:41:11.000000000 +0200
+++ dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/apps/mdfdsman.cc	2018-01-23 16:08:21.239644400 +0100
@@ -105,7 +105,7 @@
     {
         key = dicent->getKey();
     }
-    dcmDataDict.unlock();
+    dcmDataDict.rdunlock();
     return key;
 }
 
@@ -724,7 +724,7 @@
     const DcmDataDictionary& globalDataDict = dcmDataDict.rdlock();
     const DcmDictEntry *dicent = globalDataDict.findEntry(search_key,NULL);
     // successfull lookup in dictionary -> translate to tag and return
-    dcmDataDict.unlock();
+    dcmDataDict.rdunlock();
     if (dicent)
         return OFTrue;
     else return OFFalse;
diff -Nur dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/include/dcmtk/dcmdata/dcdict.h dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/include/dcmtk/dcmdata/dcdict.h
--- dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/include/dcmtk/dcmdata/dcdict.h	2017-07-14 17:41:11.000000000 +0200
+++ dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/include/dcmtk/dcmdata/dcdict.h	2018-01-23 15:12:37.143696900 +0100
@@ -238,7 +238,8 @@
 
   /** unlocks the read or write lock which must have been acquired previously.
    */
-  void unlock();
+  void rdunlock();
+  void wrunlock();
 
   /** checks if a data dictionary has been loaded. This method acquires and
    *  releases a read lock. It must not be called with another lock on the
diff -Nur dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/libsrc/dcdict.cc dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/libsrc/dcdict.cc
--- dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/libsrc/dcdict.cc	2017-07-14 17:41:11.000000000 +0200
+++ dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/libsrc/dcdict.cc	2018-01-23 15:13:09.880569700 +0100
@@ -815,7 +815,7 @@
   if (!dataDict)
     dataDict = new DcmDataDictionary(OFTrue /*loadBuiltin*/, loadExternal);
 #ifdef WITH_THREADS
-  dataDictLock.unlock();
+  dataDictLock.wrunlock();
 #endif
 }
 
@@ -828,7 +828,7 @@
   {
     /* dataDictLock must not be locked during createDataDict() */
 #ifdef WITH_THREADS
-    dataDictLock.unlock();
+    dataDictLock.rdunlock();
 #endif
     createDataDict();
 #ifdef WITH_THREADS
@@ -847,7 +847,7 @@
   {
     /* dataDictLock must not be locked during createDataDict() */
 #ifdef WITH_THREADS
-    dataDictLock.unlock();
+    dataDictLock.wrunlock();
 #endif
     createDataDict();
 #ifdef WITH_THREADS
@@ -857,22 +857,36 @@
   return *dataDict;
 }
 
-void GlobalDcmDataDictionary::unlock()
+// void GlobalDcmDataDictionary::unlock()
+// {
+// #ifdef WITH_THREADS
+//   dataDictLock.unlock();
+// #endif
+// }
+
+void GlobalDcmDataDictionary::rdunlock()
+{
+#ifdef WITH_THREADS
+  dataDictLock.rdunlock();
+#endif
+}
+
+void GlobalDcmDataDictionary::wrunlock()
 {
 #ifdef WITH_THREADS
-  dataDictLock.unlock();
+    dataDictLock.wrunlock();
 #endif
 }
 
 OFBool GlobalDcmDataDictionary::isDictionaryLoaded()
 {
   OFBool result = rdlock().isDictionaryLoaded();
-  unlock();
+  rdunlock();
   return result;
 }
 
 void GlobalDcmDataDictionary::clear()
 {
   wrlock().clear();
-  unlock();
+  wrunlock();
 }
diff -Nur dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/libsrc/dctag.cc dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/libsrc/dctag.cc
--- dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/libsrc/dctag.cc	2017-07-14 17:41:11.000000000 +0200
+++ dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/libsrc/dctag.cc	2018-01-23 15:13:32.029332900 +0100
@@ -129,7 +129,7 @@
         vr = dictRef->getVR();
         errorFlag = EC_Normal;
     }
-    dcmDataDict.unlock();
+    dcmDataDict.rdunlock();
 }
 
 // ********************************
@@ -162,7 +162,7 @@
     if (newTagName == NULL)
         newTagName = DcmTag_ERROR_TagName;
     updateTagName(newTagName);
-    dcmDataDict.unlock();
+    dcmDataDict.rdunlock();
 
     if (tagName)
         return tagName;
@@ -222,7 +222,7 @@
             }
             else
                 result = EC_TagNotFound;
-            dcmDataDict.unlock();
+            dcmDataDict.rdunlock();
         }
     }
     return result;
diff -Nur dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/tests/tnewdcme.cc dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/tests/tnewdcme.cc
--- dcmtk-for-dcmjp2k-3.6.2-unix/dcmdata/tests/tnewdcme.cc	2017-07-14 17:41:11.000000000 +0200
+++ dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmdata/tests/tnewdcme.cc	2018-01-23 15:13:38.470173500 +0100
@@ -43,7 +43,7 @@
 {
   DcmDataDictionary &dict = dcmDataDict.wrlock();
   dict.addEntry(new DcmDictEntry(PRIVATE_ELEMENT_STRINGELEM, EVR_LO, "StringAttributeForTesting", 1, 1, "private", OFTrue, PRIVATE_CREATOR_NAME));
-  dcmDataDict.unlock();
+  dcmDataDict.wrunlock();
 
 }
 
diff -Nur dcmtk-for-dcmjp2k-3.6.2-unix/dcmiod/libsrc/iodutil.cc dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmiod/libsrc/iodutil.cc
--- dcmtk-for-dcmjp2k-3.6.2-unix/dcmiod/libsrc/iodutil.cc	2017-07-14 17:41:11.000000000 +0200
+++ dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmiod/libsrc/iodutil.cc	2018-01-23 15:13:46.391194600 +0100
@@ -556,7 +556,7 @@
   {
     vr = dictRef->getVR();
   }
-  dcmDataDict.unlock();
+  dcmDataDict.rdunlock();
   if (vr.getEVR() == EVR_SQ)
     return OFTrue;
   return OFFalse;
diff -Nur dcmtk-for-dcmjp2k-3.6.2-unix/dcmnet/apps/movescu.cc dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmnet/apps/movescu.cc
--- dcmtk-for-dcmjp2k-3.6.2-unix/dcmnet/apps/movescu.cc	2017-07-14 17:41:11.000000000 +0200
+++ dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmnet/apps/movescu.cc	2018-01-23 15:14:04.574071000 +0100
@@ -168,7 +168,7 @@
       DcmTagKey key(0xffff,0xffff);
       const DcmDataDictionary& globalDataDict = dcmDataDict.rdlock();
       const DcmDictEntry *dicent = globalDataDict.findEntry(dicName.c_str());
-      dcmDataDict.unlock();
+      dcmDataDict.rdunlock();
       if (dicent!=NULL) {
         // found dictionary name, copy group and element number
         key = dicent->getKey();
diff -Nur dcmtk-for-dcmjp2k-3.6.2-unix/dcmpstat/apps/dcmpschk.cc dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmpstat/apps/dcmpschk.cc
--- dcmtk-for-dcmjp2k-3.6.2-unix/dcmpstat/apps/dcmpschk.cc	2017-07-14 17:41:11.000000000 +0200
+++ dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmpstat/apps/dcmpschk.cc	2018-01-23 15:15:19.179049600 +0100
@@ -245,7 +245,7 @@
 
     if (dictRef && (t.getEVR() == EVR_up) && (t.getEVR() == dictRef->getEVR())) result = OFTrue;
 
-    dcmDataDict.unlock();
+    dcmDataDict.rdunlock();
     return result;
 }
 
@@ -557,7 +557,7 @@
       } //end of if (isaStringVR(vr))
 
     }
-    dcmDataDict.unlock();
+    dcmDataDict.rdunlock();
     return 0;
 }
 
diff -Nur dcmtk-for-dcmjp2k-3.6.2-unix/dcmsign/apps/dcmsign.cc dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmsign/apps/dcmsign.cc
--- dcmtk-for-dcmjp2k-3.6.2-unix/dcmsign/apps/dcmsign.cc	2017-07-14 17:41:11.000000000 +0200
+++ dcmtk-for-dcmjp2k-3.6.2-unix.patched/dcmsign/apps/dcmsign.cc	2018-01-23 15:15:31.011522400 +0100
@@ -100,7 +100,7 @@
     {
       if (EC_Normal == tagList.putTagVal(dicent->getKey(), tagList.getVM())) result = OFTrue;
     }
-    dcmDataDict.unlock();
+    dcmDataDict.rdunlock();
   } else {
     if (EC_Normal == tagList.putTagVal(DcmTagKey(group,elem), tagList.getVM())) result = OFTrue;
   }
@@ -158,11 +158,11 @@
   if (dicent)
   {
     key = dicent->getKey();
-    dcmDataDict.unlock();
+    dcmDataDict.rdunlock();
     pos = lpos;
     return 1; // tag key;
   }
-  dcmDataDict.unlock();
+  dcmDataDict.rdunlock();
   OFLOG_ERROR(dcmsignLogger, "attribute name '" << aString.c_str() << "' unknown.");
   return 0; // parse error
 }
diff -Nur dcmtk-for-dcmjp2k-3.6.2-unix/ofstd/include/dcmtk/ofstd/ofthread.h dcmtk-for-dcmjp2k-3.6.2-unix.patched/ofstd/include/dcmtk/ofstd/ofthread.h
--- dcmtk-for-dcmjp2k-3.6.2-unix/ofstd/include/dcmtk/ofstd/ofthread.h	2017-07-14 17:41:11.000000000 +0200
+++ dcmtk-for-dcmjp2k-3.6.2-unix.patched/ofstd/include/dcmtk/ofstd/ofthread.h	2018-01-23 15:16:11.185530700 +0100
@@ -353,6 +353,8 @@
    *  @return 0 upon success, an error code otherwise.
    */
   int lock();
+  int rdlock();
+  int wrlock();
 
   /** tries to lock the mutex object. If the mutex is already locked,
    *  returns OFMutex::busy.
@@ -360,6 +362,8 @@
    *    an error code otherwise.
    */
   int trylock();
+  int tryrdlock();
+  int trywrlock();
 
   /** releases the lock on the mutex object. The mutex must be locked and
    *  the calling thread must be the owner of the lock, otherwise the
@@ -369,6 +373,8 @@
    *  @return 0 upon success, an error code otherwise.
    */
   int unlock();
+  int rdunlock();
+  int wrunlock();
 
   /** converts any of the error codes returned by the methods of this class
    *  into a textual description, which is written into the string object.
@@ -459,6 +465,8 @@
    *  @return 0 upon success, an error code otherwise.
    */
   int unlock();
+  int rdunlock();
+  int wrunlock();
 
   /** converts any of the error codes returned by the methods of this class
    *  into a textual description, which is written into the string object.
diff -Nur dcmtk-for-dcmjp2k-3.6.2-unix/ofstd/libsrc/ofthread.cc dcmtk-for-dcmjp2k-3.6.2-unix.patched/ofstd/libsrc/ofthread.cc
--- dcmtk-for-dcmjp2k-3.6.2-unix/ofstd/libsrc/ofthread.cc	2017-07-14 17:41:11.000000000 +0200
+++ dcmtk-for-dcmjp2k-3.6.2-unix.patched/ofstd/libsrc/ofthread.cc	2018-01-23 15:17:43.191052100 +0100
@@ -595,9 +595,12 @@
 #ifdef USE_WIN32_CREATE_MUTEX
   theMutex = OFstatic_cast(void *, CreateMutex(NULL, FALSE, NULL));
 #else
-  CRITICAL_SECTION *critSec = new CRITICAL_SECTION;
-  InitializeCriticalSection(critSec);
-  theMutex = OFstatic_cast(void *, critSec);
+  //CRITICAL_SECTION *critSec = new CRITICAL_SECTION;
+  //InitializeCriticalSection(critSec);
+  //theMutex = OFstatic_cast(void *, critSec);
+  SRWLOCK* srwLock = new SRWLOCK;
+  InitializeSRWLock(srwLock);
+  theMutex = OFstatic_cast(void*, srwLock);
 #endif
 #elif defined(POSIX_INTERFACE)
   pthread_mutex_t *mtx = new pthread_mutex_t;
@@ -624,9 +627,11 @@
 #ifdef USE_WIN32_CREATE_MUTEX
   CloseHandle(OFthread_cast(HANDLE, theMutex));
 #else
-  CRITICAL_SECTION *critSec = OFthread_cast(CRITICAL_SECTION *, theMutex);
-  DeleteCriticalSection(critSec);
-  delete critSec;
+//   CRITICAL_SECTION *critSec = OFthread_cast(CRITICAL_SECTION *, theMutex);
+//   DeleteCriticalSection(critSec);
+//   delete critSec;
+    SRWLOCK* srwLock = OFthread_cast(SRWLOCK*, theMutex); // no explicit destruction is necessary
+    delete srwLock;
 #endif
 #elif defined(POSIX_INTERFACE)
   if (theMutex) pthread_mutex_destroy(OFthread_cast(pthread_mutex_t *, theMutex));
@@ -657,7 +662,48 @@
   if (WaitForSingleObject(OFthread_cast(HANDLE, theMutex), INFINITE) == WAIT_OBJECT_0) return 0;
   else return OFstatic_cast(int, GetLastError());
 #else
-  EnterCriticalSection(OFthread_cast(CRITICAL_SECTION *, theMutex));
+  //EnterCriticalSection(OFthread_cast(CRITICAL_SECTION *, theMutex));
+  AcquireSRWLockExclusive(OFthread_cast(SRWLOCK*, theMutex));
+  return 0;
+#endif
+#elif defined(POSIX_INTERFACE)
+  if (theMutex) return pthread_mutex_lock(OFthread_cast(pthread_mutex_t *, theMutex)); else return EINVAL;
+#elif defined(SOLARIS_INTERFACE)
+  if (theMutex) return mutex_lock(OFthread_cast(mutex_t *, theMutex)); else return EINVAL;
+#else
+  return -1;
+#endif
+}
+
+int OFMutex::rdlock()
+{
+#ifdef WINDOWS_INTERFACE
+#ifdef USE_WIN32_CREATE_MUTEX
+    if (WaitForSingleObject(OFthread_cast(HANDLE, theMutex), INFINITE) == WAIT_OBJECT_0) return 0;
+    else return OFstatic_cast(int, GetLastError());
+#else
+    //EnterCriticalSection(OFthread_cast(CRITICAL_SECTION *, theMutex));
+    AcquireSRWLockShared(OFthread_cast(SRWLOCK*, theMutex));
+    return 0;
+#endif
+#elif defined(POSIX_INTERFACE)
+    if (theMutex) return pthread_mutex_lock(OFthread_cast(pthread_mutex_t *, theMutex)); else return EINVAL;
+#elif defined(SOLARIS_INTERFACE)
+    if (theMutex) return mutex_lock(OFthread_cast(mutex_t *, theMutex)); else return EINVAL;
+#else
+    return -1;
+#endif
+}
+
+int OFMutex::wrlock()
+{
+#ifdef WINDOWS_INTERFACE
+#ifdef USE_WIN32_CREATE_MUTEX
+    if (WaitForSingleObject(OFthread_cast(HANDLE, theMutex), INFINITE) == WAIT_OBJECT_0) return 0;
+    else return OFstatic_cast(int, GetLastError());
+#else
+    //EnterCriticalSection(OFthread_cast(CRITICAL_SECTION *, theMutex));
+    AcquireSRWLockExclusive(OFthread_cast(SRWLOCK*, theMutex));
   return 0;
 #endif
 #elif defined(POSIX_INTERFACE)
@@ -678,7 +724,52 @@
   else if (result == WAIT_TIMEOUT) return OFMutex::busy;
   else return OFstatic_cast(int, GetLastError());
 #else
-  if (TryEnterCriticalSection(OFthread_cast(CRITICAL_SECTION *, theMutex))) return 0;
+  //if (TryEnterCriticalSection(OFthread_cast(CRITICAL_SECTION *, theMutex))) return 0;
+    if (TryAcquireSRWLockExclusive(OFthread_cast(SRWLOCK*, theMutex))) return 0;
+  else return OFMutex::busy;
+#endif
+#elif defined(POSIX_INTERFACE)
+  if (theMutex) return pthread_mutex_trylock(OFthread_cast(pthread_mutex_t *, theMutex)); else return EINVAL; // may return EBUSY.
+#elif defined(SOLARIS_INTERFACE)
+  if (theMutex) return mutex_trylock(OFthread_cast(mutex_t *, theMutex)); else return EINVAL; // may return EBUSY.
+#else
+  return -1;
+#endif
+}
+
+int OFMutex::tryrdlock()
+{
+#ifdef WINDOWS_INTERFACE
+#ifdef USE_WIN32_CREATE_MUTEX
+    DWORD result = WaitForSingleObject(OFthread_cast(HANDLE, theMutex), 0);
+    if (result == WAIT_OBJECT_0) return 0;
+    else if (result == WAIT_TIMEOUT) return OFMutex::busy;
+    else return OFstatic_cast(int, GetLastError());
+#else
+    //if (TryEnterCriticalSection(OFthread_cast(CRITICAL_SECTION *, theMutex))) return 0;
+    if (TryAcquireSRWLockShared(OFthread_cast(SRWLOCK*, theMutex))) return 0;
+    else return OFMutex::busy;
+#endif
+#elif defined(POSIX_INTERFACE)
+    if (theMutex) return pthread_mutex_trylock(OFthread_cast(pthread_mutex_t *, theMutex)); else return EINVAL; // may return EBUSY.
+#elif defined(SOLARIS_INTERFACE)
+    if (theMutex) return mutex_trylock(OFthread_cast(mutex_t *, theMutex)); else return EINVAL; // may return EBUSY.
+#else
+    return -1;
+#endif
+}
+
+int OFMutex::trywrlock()
+{
+#ifdef WINDOWS_INTERFACE
+#ifdef USE_WIN32_CREATE_MUTEX
+    DWORD result = WaitForSingleObject(OFthread_cast(HANDLE, theMutex), 0);
+    if (result == WAIT_OBJECT_0) return 0;
+    else if (result == WAIT_TIMEOUT) return OFMutex::busy;
+    else return OFstatic_cast(int, GetLastError());
+#else
+    //if (TryEnterCriticalSection(OFthread_cast(CRITICAL_SECTION *, theMutex))) return 0;
+    if (TryAcquireSRWLockExclusive(OFthread_cast(SRWLOCK*, theMutex))) return 0;
   else return OFMutex::busy;
 #endif
 #elif defined(POSIX_INTERFACE)
@@ -696,7 +787,46 @@
 #ifdef USE_WIN32_CREATE_MUTEX
   if (ReleaseMutex(OFthread_cast(HANDLE, theMutex))) return 0; else return OFstatic_cast(int, GetLastError());
 #else
-  LeaveCriticalSection(OFthread_cast(CRITICAL_SECTION *, theMutex));
+  //LeaveCriticalSection(OFthread_cast(CRITICAL_SECTION *, theMutex));
+  ReleaseSRWLockExclusive(OFthread_cast(SRWLOCK*, theMutex));
+  return 0;
+#endif
+#elif defined(POSIX_INTERFACE)
+  if (theMutex) return pthread_mutex_unlock(OFthread_cast(pthread_mutex_t *, theMutex)); else return EINVAL;
+#elif defined(SOLARIS_INTERFACE)
+  if (theMutex) return mutex_unlock(OFthread_cast(mutex_t *, theMutex)); else return EINVAL;
+#else
+  return -1;
+#endif
+}
+
+int OFMutex::rdunlock()
+{
+#ifdef WINDOWS_INTERFACE
+#ifdef USE_WIN32_CREATE_MUTEX
+    if (ReleaseMutex(OFthread_cast(HANDLE, theMutex))) return 0; else return OFstatic_cast(int, GetLastError());
+#else
+    //LeaveCriticalSection(OFthread_cast(CRITICAL_SECTION *, theMutex));
+    ReleaseSRWLockShared(OFthread_cast(SRWLOCK*, theMutex));
+    return 0;
+#endif
+#elif defined(POSIX_INTERFACE)
+    if (theMutex) return pthread_mutex_unlock(OFthread_cast(pthread_mutex_t *, theMutex)); else return EINVAL;
+#elif defined(SOLARIS_INTERFACE)
+    if (theMutex) return mutex_unlock(OFthread_cast(mutex_t *, theMutex)); else return EINVAL;
+#else
+    return -1;
+#endif
+}
+
+int OFMutex::wrunlock()
+{
+#ifdef WINDOWS_INTERFACE
+#ifdef USE_WIN32_CREATE_MUTEX
+    if (ReleaseMutex(OFthread_cast(HANDLE, theMutex))) return 0; else return OFstatic_cast(int, GetLastError());
+#else
+    //LeaveCriticalSection(OFthread_cast(CRITICAL_SECTION *, theMutex));
+    ReleaseSRWLockExclusive(OFthread_cast(SRWLOCK*, theMutex));
   return 0;
 #endif
 #elif defined(POSIX_INTERFACE)
@@ -822,28 +952,7 @@
   if (theLock)
   {
     OFReadWriteLockHelper *rwl = OFthread_cast(OFReadWriteLockHelper *, theLock);
-    int result =0;
-    while (1)
-    {
-      if (0 != (result = rwl->accessMutex.lock())) return result; // lock mutex
-      if (rwl->numReaders >= 0) // we can grant the read lock
-      {
-        if (rwl->numReaders == 0)
-        {
-          if (0 != (result = rwl->usageSemaphore.wait()))
-          {
-            rwl->accessMutex.unlock();
-            return result;
-          }
-        }
-        (rwl->numReaders)++;
-        return rwl->accessMutex.unlock();
-      }
-      // we cannot grant the read lock, block thread.
-      if (0 != (result = rwl->accessMutex.unlock())) return result;
-      if (0 != (result = rwl->usageSemaphore.wait())) return result;
-      if (0 != (result = rwl->usageSemaphore.post())) return result;
-    }
+    return rwl->accessMutex.rdlock();
   } else return EINVAL;
 #elif defined(POSIX_INTERFACE)
   if (theLock) return pthread_rwlock_rdlock(OFthread_cast(pthread_rwlock_t *, theLock)); else return EINVAL;
@@ -860,26 +969,7 @@
   if (theLock)
   {
     OFReadWriteLockHelper *rwl = OFthread_cast(OFReadWriteLockHelper *, theLock);
-    int result =0;
-    while (1)
-    {
-      if (0 != (result = rwl->accessMutex.lock())) return result; // lock mutex
-      if (rwl->numReaders == 0) // we can grant the write lock
-      {
-        if (0 != (result = rwl->usageSemaphore.wait()))
-        {
-          rwl->accessMutex.unlock();
-          return result;
-        }
-        rwl->numReaders = -1;
-        return rwl->accessMutex.unlock();
-      }
-
-      // we cannot grant the write lock, block thread.
-      if (0 != (result = rwl->accessMutex.unlock())) return result;
-      if (0 != (result = rwl->usageSemaphore.wait())) return result;
-      if (0 != (result = rwl->usageSemaphore.post())) return result;
-    }
+    return rwl->accessMutex.wrlock();
   } else return EINVAL;
 #elif defined(POSIX_INTERFACE)
   if (theLock) return pthread_rwlock_wrlock(OFthread_cast(pthread_rwlock_t *, theLock)); else return EINVAL;
@@ -897,23 +987,7 @@
   if (theLock)
   {
     OFReadWriteLockHelper *rwl = OFthread_cast(OFReadWriteLockHelper *, theLock);
-    int result =0;
-    if (0 != (result = rwl->accessMutex.lock())) return result; // lock mutex
-    if (rwl->numReaders >= 0) // we can grant the read lock
-    {
-      if (rwl->numReaders == 0)
-      {
-        if (0 != (result = rwl->usageSemaphore.wait()))
-        {
-          rwl->accessMutex.unlock();
-          return result;
-        }
-      }
-      (rwl->numReaders)++;
-      return rwl->accessMutex.unlock();
-    }
-    result = rwl->accessMutex.unlock();
-    if (result) return result; else return OFReadWriteLock::busy;
+    return rwl->accessMutex.tryrdlock();
   } else return EINVAL;
 #elif defined(POSIX_INTERFACE)
   if (theLock) return pthread_rwlock_tryrdlock(OFthread_cast(pthread_rwlock_t *, theLock)); else return EINVAL; // may return EBUSY.
@@ -930,20 +1004,7 @@
   if (theLock)
   {
     OFReadWriteLockHelper *rwl = OFthread_cast(OFReadWriteLockHelper *, theLock);
-    int result =0;
-    if (0 != (result = rwl->accessMutex.lock())) return result; // lock mutex
-    if (rwl->numReaders == 0) // we can grant the write lock
-    {
-      if (0 != (result = rwl->usageSemaphore.wait()))
-      {
-        rwl->accessMutex.unlock();
-        return result;
-      }
-      rwl->numReaders = -1;
-      return rwl->accessMutex.unlock();
-    }
-    result = rwl->accessMutex.unlock();
-    if (result) return result; else return OFReadWriteLock::busy;
+    return rwl->accessMutex.trywrlock();
   } else return EINVAL;
 #elif defined(POSIX_INTERFACE)
   if (theLock) return pthread_rwlock_trywrlock(OFthread_cast(pthread_rwlock_t *, theLock)); else return EINVAL; // may return EBUSY.
@@ -961,18 +1022,44 @@
   if (theLock)
   {
     OFReadWriteLockHelper *rwl = OFthread_cast(OFReadWriteLockHelper *, theLock);
-    int result =0;
-    if (0 != (result = rwl->accessMutex.lock())) return result; // lock mutex
-    if (rwl->numReaders == -1) rwl->numReaders = 0; else (rwl->numReaders)--;
-    if ((rwl->numReaders == 0) && (0 != (result = rwl->usageSemaphore.post())))
-    {
-      rwl->accessMutex.unlock();
-      return result;
-    }
     return rwl->accessMutex.unlock();
   } else return EINVAL;
 #elif defined(POSIX_INTERFACE)
   if (theLock) return pthread_rwlock_unlock(OFthread_cast(pthread_rwlock_t *, theLock)); else return EINVAL;
+#elif defined(SOLARIS_INTERFACE)
+  if (theLock) return rw_unlock(OFthread_cast(rwlock_t *, theLock)); else return EINVAL;
+#else
+  return -1;
+#endif
+}
+
+int OFReadWriteLock::rdunlock()
+{
+#if defined(WINDOWS_INTERFACE) || defined(POSIX_INTERFACE_WITHOUT_RWLOCK)
+    if (theLock)
+    {
+        OFReadWriteLockHelper *rwl = OFthread_cast(OFReadWriteLockHelper *, theLock);
+        return rwl->accessMutex.rdunlock();
+    } else return EINVAL;
+#elif defined(POSIX_INTERFACE)
+    if (theLock) return pthread_rwlock_unlock(OFthread_cast(pthread_rwlock_t *, theLock)); else return EINVAL;
+#elif defined(SOLARIS_INTERFACE)
+    if (theLock) return rw_unlock(OFthread_cast(rwlock_t *, theLock)); else return EINVAL;
+#else
+    return -1;
+#endif
+}
+
+int OFReadWriteLock::wrunlock()
+{
+#if defined(WINDOWS_INTERFACE) || defined(POSIX_INTERFACE_WITHOUT_RWLOCK)
+    if (theLock)
+    {
+        OFReadWriteLockHelper *rwl = OFthread_cast(OFReadWriteLockHelper *, theLock);
+        return rwl->accessMutex.wrunlock();
+  } else return EINVAL;
+#elif defined(POSIX_INTERFACE)
+  if (theLock) return pthread_rwlock_unlock(OFthread_cast(pthread_rwlock_t *, theLock)); else return EINVAL;
 #elif defined(SOLARIS_INTERFACE)
   if (theLock) return rw_unlock(OFthread_cast(rwlock_t *, theLock)); else return EINVAL;
 #else