Index: src/OFMessagePackExtension.m
==================================================================
--- src/OFMessagePackExtension.m
+++ src/OFMessagePackExtension.m
@@ -74,11 +74,11 @@
 }
 
 - (OFDataArray*)messagePackRepresentation
 {
 	OFDataArray *ret;
-	int8_t prefix;
+	uint8_t prefix;
 	size_t count = [_data count];
 
 	if (count == 1) {
 		ret = [OFDataArray dataArrayWithCapacity: 3];
 

Index: src/OFString.m
==================================================================
--- src/OFString.m
+++ src/OFString.m
@@ -76,14 +76,15 @@
 				lossy: (bool)lossy;
 - (OFString*)OF_JSONRepresentationWithOptions: (int)options
 					depth: (size_t)depth;
 @end
 
-extern bool of_unicode_to_iso_8859_15(const of_unichar_t*, char*, size_t, bool);
-extern bool of_unicode_to_windows_1252(const of_unichar_t*, char*, size_t,
+extern bool of_unicode_to_iso_8859_15(const of_unichar_t*, uint8_t*, size_t,
+    bool);
+extern bool of_unicode_to_windows_1252(const of_unichar_t*, uint8_t*, size_t,
     bool);
-extern bool of_unicode_to_codepage_437(const of_unichar_t*, char*, size_t,
+extern bool of_unicode_to_codepage_437(const of_unichar_t*, uint8_t*, size_t,
     bool);
 
 /* References for static linking */
 void _references_to_categories_of_OFString(void)
 {
@@ -1067,34 +1068,34 @@
 		return length;
 	case OF_STRING_ENCODING_ISO_8859_15:
 		if (length + 1 > maxLength)
 			@throw [OFOutOfRangeException exception];
 
-		if (!of_unicode_to_iso_8859_15(characters, cString, length,
-		    lossy))
+		if (!of_unicode_to_iso_8859_15(characters, (uint8_t*)cString,
+		    length, lossy))
 			@throw [OFInvalidEncodingException exception];
 
 		cString[length] = '\0';
 
 		return length;
 	case OF_STRING_ENCODING_WINDOWS_1252:
 		if (length + 1 > maxLength)
 			@throw [OFOutOfRangeException exception];
 
-		if (!of_unicode_to_windows_1252(characters, cString, length,
-		    lossy))
+		if (!of_unicode_to_windows_1252(characters, (uint8_t*)cString,
+		    length, lossy))
 			@throw [OFInvalidEncodingException exception];
 
 		cString[length] = '\0';
 
 		return length;
 	case OF_STRING_ENCODING_CODEPAGE_437:
 		if (length + 1 > maxLength)
 			@throw [OFOutOfRangeException exception];
 
-		if (!of_unicode_to_codepage_437(characters, cString, length,
-		    lossy))
+		if (!of_unicode_to_codepage_437(characters, (uint8_t*)cString,
+		    length, lossy))
 			@throw [OFInvalidEncodingException exception];
 
 		cString[length] = '\0';
 
 		return length;

Index: src/codepage_437.m
==================================================================
--- src/codepage_437.m
+++ src/codepage_437.m
@@ -36,11 +36,11 @@
 	0x2261, 0x00B1, 0x2265, 0x2264, 0x2320, 0x2321, 0x00F7, 0x2248,
 	0x00B0, 0x2219, 0x00B7, 0x221A, 0x207F, 0x00B2, 0x25A0, 0x00A0
 };
 
 bool
-of_unicode_to_codepage_437(const of_unichar_t *input, char *output,
+of_unicode_to_codepage_437(const of_unichar_t *input, uint8_t *output,
     size_t length, bool lossy)
 {
 	size_t i;
 
 	for (i = 0; i < length; i++) {

Index: src/iso_8859_15.m
==================================================================
--- src/iso_8859_15.m
+++ src/iso_8859_15.m
@@ -36,11 +36,11 @@
 	0x00F0, 0x00F1, 0x00F2, 0x00F3, 0x00F4, 0x00F5, 0x00F6, 0x00F7,
 	0x00F8, 0x00F9, 0x00FA, 0x00FB, 0x00FC, 0x00FD, 0x00FE, 0x00FF
 };
 
 bool
-of_unicode_to_iso_8859_15(const of_unichar_t *input, char *output,
+of_unicode_to_iso_8859_15(const of_unichar_t *input, uint8_t *output,
     size_t length, bool lossy)
 {
 	size_t i;
 
 	for (i = 0; i < length; i++) {

Index: src/windows_1252.m
==================================================================
--- src/windows_1252.m
+++ src/windows_1252.m
@@ -36,11 +36,11 @@
 	0x00F0, 0x00F1, 0x00F2, 0x00F3, 0x00F4, 0x00F5, 0x00F6, 0x00F7,
 	0x00F8, 0x00F9, 0x00FA, 0x00FB, 0x00FC, 0x00FD, 0x00FE, 0x00FF
 };
 
 bool
-of_unicode_to_windows_1252(const of_unichar_t *input, char *output,
+of_unicode_to_windows_1252(const of_unichar_t *input, uint8_t *output,
     size_t length, bool lossy)
 {
 	size_t i;
 
 	for (i = 0; i < length; i++) {