diff --git a/WINGs/WINGs/WUtil.h b/WINGs/WINGs/WUtil.h
index 6c26f612..2b462db9 100644
--- a/WINGs/WINGs/WUtil.h
+++ b/WINGs/WINGs/WUtil.h
@@ -553,7 +553,7 @@ WMData* WMCreateDataWithCapacity(unsigned capacity);
 
 WMData* WMCreateDataWithLength(unsigned length);
 
-WMData* WMCreateDataWithBytes(void *bytes, unsigned length);
+WMData* WMCreateDataWithBytes(const void *bytes, unsigned length);
 
 /* destructor is a function called to free the data when releasing the data
  * object, or NULL if no freeing of data is necesary. */
@@ -594,13 +594,13 @@ unsigned WMGetDataLength(WMData *aData);
 
 /* Adding data */
 
-void WMAppendDataBytes(WMData *aData, void *bytes, unsigned length);
+void WMAppendDataBytes(WMData *aData, const void *bytes, unsigned length);
 
 void WMAppendData(WMData *aData, WMData *anotherData);
 
 /* Modifying data */
 
-void WMReplaceDataBytesInRange(WMData *aData, WMRange aRange, void *bytes);
+void WMReplaceDataBytesInRange(WMData *aData, WMRange aRange, const void *bytes);
 
 void WMResetDataBytesInRange(WMData *aData, WMRange aRange);
 
@@ -713,11 +713,11 @@ void WMEnqueueCoalesceNotification(WMNotificationQueue *queue,
 
 void WMPLSetCaseSensitive(Bool caseSensitive);
 
-WMPropList* WMCreatePLString(char *str);
+WMPropList* WMCreatePLString(const char *str);
 
 WMPropList* WMCreatePLData(WMData *data);
 
-WMPropList* WMCreatePLDataWithBytes(unsigned char *bytes, unsigned int length);
+WMPropList* WMCreatePLDataWithBytes(const unsigned char *bytes, unsigned int length);
 
 WMPropList* WMCreatePLDataWithBytesNoCopy(unsigned char *bytes,
                                           unsigned int length,
@@ -821,7 +821,7 @@ char* wglobaldefaultspathfordomain(const char *domain);
 
 WMUserDefaults* WMGetStandardUserDefaults(void);
 
-WMUserDefaults* WMGetDefaultsFromPath(char *path);
+WMUserDefaults* WMGetDefaultsFromPath(const char *path);
 
 void WMSynchronizeUserDefaults(WMUserDefaults *database);
 
@@ -834,32 +834,32 @@ void WMEnableUDPeriodicSynchronization(WMUserDefaults *database, Bool enable);
  * Keys in array are just retained references to the original keys */
 WMPropList* WMGetUDKeys(WMUserDefaults *database);
 
-WMPropList* WMGetUDObjectForKey(WMUserDefaults *database, char *defaultName);
+WMPropList* WMGetUDObjectForKey(WMUserDefaults *database, const char *defaultName);
 
 void WMSetUDObjectForKey(WMUserDefaults *database, WMPropList *object,
-                         char *defaultName);
+                         const char *defaultName);
 
-void WMRemoveUDObjectForKey(WMUserDefaults *database, char *defaultName);
+void WMRemoveUDObjectForKey(WMUserDefaults *database, const char *defaultName);
 
-char* WMGetUDStringForKey(WMUserDefaults *database, char *defaultName);
+char* WMGetUDStringForKey(WMUserDefaults *database, const char *defaultName);
 
-int WMGetUDIntegerForKey(WMUserDefaults *database, char *defaultName);
+int WMGetUDIntegerForKey(WMUserDefaults *database, const char *defaultName);
 
-float WMGetUDFloatForKey(WMUserDefaults *database, char *defaultName);
+float WMGetUDFloatForKey(WMUserDefaults *database, const char *defaultName);
 
-Bool WMGetUDBoolForKey(WMUserDefaults *database, char *defaultName);
+Bool WMGetUDBoolForKey(WMUserDefaults *database, const char *defaultName);
 
-void WMSetUDStringForKey(WMUserDefaults *database, char *value,
-                         char *defaultName);
+void WMSetUDStringForKey(WMUserDefaults *database, const char *value,
+                         const char *defaultName);
 
 void WMSetUDIntegerForKey(WMUserDefaults *database, int value,
-                          char *defaultName);
+                          const char *defaultName);
 
 void WMSetUDFloatForKey(WMUserDefaults *database, float value,
-                        char *defaultName);
+                        const char *defaultName);
 
 void WMSetUDBoolForKey(WMUserDefaults *database, Bool value,
-                       char *defaultName);
+                       const char *defaultName);
 
 WMPropList* WMGetUDSearchList(WMUserDefaults *database);
 
diff --git a/WINGs/data.c b/WINGs/data.c
index c1c11a6b..f4489099 100644
--- a/WINGs/data.c
+++ b/WINGs/data.c
@@ -67,7 +67,7 @@ WMData *WMCreateDataWithLength(unsigned length)
 	return aData;
 }
 
-WMData *WMCreateDataWithBytes(void *bytes, unsigned length)
+WMData *WMCreateDataWithBytes(const void *bytes, unsigned length)
 {
 	WMData *aData;
 
@@ -230,7 +230,7 @@ unsigned WMGetDataLength(WMData * aData)
 }
 
 /* Adding data */
-void WMAppendDataBytes(WMData * aData, void *bytes, unsigned length)
+void WMAppendDataBytes(WMData * aData, const void *bytes, unsigned length)
 {
 	unsigned oldLength = aData->length;
 	unsigned newLength = oldLength + length;
@@ -260,7 +260,7 @@ void WMAppendData(WMData * aData, WMData * anotherData)
 
 /* Modifying data */
 
-void WMReplaceDataBytesInRange(WMData * aData, WMRange aRange, void *bytes)
+void WMReplaceDataBytesInRange(WMData * aData, WMRange aRange, const void *bytes)
 {
 	wassertr(aRange.position < aData->length);
 	wassertr(aRange.count <= aData->length - aRange.position);
diff --git a/WINGs/proplist.c b/WINGs/proplist.c
index 7e8ff2c3..1243354b 100644
--- a/WINGs/proplist.c
+++ b/WINGs/proplist.c
@@ -885,7 +885,7 @@ void WMPLSetCaseSensitive(Bool caseSensitiveness)
 	caseSensitive = caseSensitiveness;
 }
 
-WMPropList *WMCreatePLString(char *str)
+WMPropList *WMCreatePLString(const char *str)
 {
 	WMPropList *plist;
 
@@ -913,7 +913,7 @@ WMPropList *WMCreatePLData(WMData * data)
 	return plist;
 }
 
-WMPropList *WMCreatePLDataWithBytes(unsigned char *bytes, unsigned int length)
+WMPropList *WMCreatePLDataWithBytes(const unsigned char *bytes, unsigned int length)
 {
 	WMPropList *plist;
 
diff --git a/WINGs/userdefaults.c b/WINGs/userdefaults.c
index 96575a03..7dd9931a 100644
--- a/WINGs/userdefaults.c
+++ b/WINGs/userdefaults.c
@@ -340,13 +340,13 @@ WMUserDefaults *WMGetStandardUserDefaults(void)
 	return defaults;
 }
 
-WMUserDefaults *WMGetDefaultsFromPath(char *path)
+WMUserDefaults *WMGetDefaultsFromPath(const char *path)
 {
 	WMUserDefaults *defaults;
 	WMPropList *domain;
 	WMPropList *key;
 	struct stat stbuf;
-	char *name;
+	const char *name;
 	int i;
 
 	assert(path != NULL);
@@ -421,7 +421,7 @@ WMPropList *WMGetUDKeys(WMUserDefaults * database)
 	return WMGetPLDictionaryKeys(database->appDomain);
 }
 
-WMPropList *WMGetUDObjectForKey(WMUserDefaults * database, char *defaultName)
+WMPropList *WMGetUDObjectForKey(WMUserDefaults * database, const char *defaultName)
 {
 	WMPropList *domainName, *domain;
 	WMPropList *object = NULL;
@@ -441,7 +441,7 @@ WMPropList *WMGetUDObjectForKey(WMUserDefaults * database, char *defaultName)
 	return object;
 }
 
-void WMSetUDObjectForKey(WMUserDefaults * database, WMPropList * object, char *defaultName)
+void WMSetUDObjectForKey(WMUserDefaults * database, WMPropList * object, const char *defaultName)
 {
 	WMPropList *key = WMCreatePLString(defaultName);
 
@@ -451,7 +451,7 @@ void WMSetUDObjectForKey(WMUserDefaults * database, WMPropList * object, char *d
 	WMReleasePropList(key);
 }
 
-void WMRemoveUDObjectForKey(WMUserDefaults * database, char *defaultName)
+void WMRemoveUDObjectForKey(WMUserDefaults * database, const char *defaultName)
 {
 	WMPropList *key = WMCreatePLString(defaultName);
 
@@ -462,7 +462,7 @@ void WMRemoveUDObjectForKey(WMUserDefaults * database, char *defaultName)
 	WMReleasePropList(key);
 }
 
-char *WMGetUDStringForKey(WMUserDefaults * database, char *defaultName)
+char *WMGetUDStringForKey(WMUserDefaults * database, const char *defaultName)
 {
 	WMPropList *val;
 
@@ -477,7 +477,7 @@ char *WMGetUDStringForKey(WMUserDefaults * database, char *defaultName)
 	return WMGetFromPLString(val);
 }
 
-int WMGetUDIntegerForKey(WMUserDefaults * database, char *defaultName)
+int WMGetUDIntegerForKey(WMUserDefaults * database, const char *defaultName)
 {
 	WMPropList *val;
 	char *str;
@@ -501,7 +501,7 @@ int WMGetUDIntegerForKey(WMUserDefaults * database, char *defaultName)
 	return value;
 }
 
-float WMGetUDFloatForKey(WMUserDefaults * database, char *defaultName)
+float WMGetUDFloatForKey(WMUserDefaults * database, const char *defaultName)
 {
 	WMPropList *val;
 	char *str;
@@ -521,7 +521,7 @@ float WMGetUDFloatForKey(WMUserDefaults * database, char *defaultName)
 	return value;
 }
 
-Bool WMGetUDBoolForKey(WMUserDefaults * database, char *defaultName)
+Bool WMGetUDBoolForKey(WMUserDefaults * database, const char *defaultName)
 {
 	WMPropList *val;
 	int value;
@@ -551,7 +551,7 @@ Bool WMGetUDBoolForKey(WMUserDefaults * database, char *defaultName)
 	return False;
 }
 
-void WMSetUDIntegerForKey(WMUserDefaults * database, int value, char *defaultName)
+void WMSetUDIntegerForKey(WMUserDefaults * database, int value, const char *defaultName)
 {
 	WMPropList *object;
 	char buffer[128];
@@ -563,7 +563,7 @@ void WMSetUDIntegerForKey(WMUserDefaults * database, int value, char *defaultNam
 	WMReleasePropList(object);
 }
 
-void WMSetUDStringForKey(WMUserDefaults * database, char *value, char *defaultName)
+void WMSetUDStringForKey(WMUserDefaults * database, const char *value, const char *defaultName)
 {
 	WMPropList *object;
 
@@ -573,7 +573,7 @@ void WMSetUDStringForKey(WMUserDefaults * database, char *value, char *defaultNa
 	WMReleasePropList(object);
 }
 
-void WMSetUDFloatForKey(WMUserDefaults * database, float value, char *defaultName)
+void WMSetUDFloatForKey(WMUserDefaults * database, float value, const char *defaultName)
 {
 	WMPropList *object;
 	char buffer[128];
@@ -585,7 +585,7 @@ void WMSetUDFloatForKey(WMUserDefaults * database, float value, char *defaultNam
 	WMReleasePropList(object);
 }
 
-void WMSetUDBoolForKey(WMUserDefaults * database, Bool value, char *defaultName)
+void WMSetUDBoolForKey(WMUserDefaults * database, Bool value, const char *defaultName)
 {
 	static WMPropList *yes = NULL, *no = NULL;