Index: src/OFString.m
==================================================================
--- src/OFString.m
+++ src/OFString.m
@@ -30,13 +30,13 @@
 		if (str == NULL) {
 			length = 0;
 			string = NULL;
 		} else {
 			length = strlen(str);
-			if ((string = [self getMem: length]) == NULL)
+			if ((string = [self getMem: length + 1]) == NULL)
 				return NULL;
-			memcpy(string, str, length);
+			memcpy(string, str, length + 1);
 		}
 	}
 	return self;
 }
 
@@ -63,13 +63,13 @@
 
 		return self;
 	}
 
 	newlen = strlen(str);
-	if ((newstr = [self getMem: newlen]) == NULL)
+	if ((newstr = [self getMem: newlen + 1]) == NULL)
 		return nil;
-	memcpy(newstr, str, newlen);
+	memcpy(newstr, str, newlen + 1);
 
 	if (string != NULL)
 		[self freeMem: string];
 
 	length = newlen;
@@ -97,15 +97,13 @@
 	/* FIXME: Add error handling */
 	if ((newstr = [self resizeMem: string
 			       toSize: newlen + 1]) == NULL)
 		return nil;
 
-	string = newstr;
-
-	memcpy(string + length, str, strlength);
-	string[newlen] = '\0';
+	memcpy(newstr + length, str, strlength + 1);
 
 	length = newlen;
+	string = newstr;
 
 	return self;
 }
 @end

Index: src/OFWideString.m
==================================================================
--- src/OFWideString.m
+++ src/OFWideString.m
@@ -31,14 +31,14 @@
 		if (wstr == NULL) {
 			length = 0;
 			wstring = NULL;
 		} else {
 			length = wcslen(wstr);
-			if ((wstring =
-			    [self getMem: length * sizeof(wchar_t)]) == NULL)
+			if (NULL == (wstring =
+			    [self getMem: (length + 1) * sizeof(wchar_t)]))
 				return NULL;
-			memcpy(wstring, wstr, length * sizeof(wchar_t));
+			memcpy(wstring, wstr, (length + 1) * sizeof(wchar_t));
 		}
 	}
 	return self;
 }
 
@@ -65,13 +65,13 @@
 
 		return self;
 	}
 
 	newlen = wcslen(wstr);
-	if ((newstr = [self getMem: newlen * sizeof(wchar_t)]) == NULL)
+	if ((newstr = [self getMem: (newlen + 1) * sizeof(wchar_t)]) == NULL)
 		return nil;
-	memcpy(newstr, wstr, newlen * sizeof(wchar_t));
+	memcpy(newstr, wstr, (newlen + 1) * sizeof(wchar_t));
 
 	if (wstring != NULL)
 		[self freeMem: wstring];
 
 	length = newlen;
@@ -96,19 +96,18 @@
 	strlength = wcslen(wstr);
 	newlen = length + strlength;
 
 	/* FIXME: Add error handling */
 	if ((newstr = [self resizeMem: wstring
-			       toSize: newlen  * sizeof(wchar_t) + 2]) == NULL)
+			       toSize: (newlen + 1 ) * sizeof(wchar_t)]) == 
+	    NULL)
 		return nil;
 
-	wstring = newstr;
-
-	memcpy(wstring + length * sizeof(wchar_t), wstr,
-	    strlength * sizeof(wchar_t));
-	wstring[newlen] = '\0';
+	memcpy(newstr + length * sizeof(wchar_t), wstr,
+	    (strlength + 1) * sizeof(wchar_t));
 
 	length = newlen;
+	wstring = newstr;
 
 	return self;
 }
 @end

Index: tests/OFWideString/OFWideString.m
==================================================================
--- tests/OFWideString/OFWideString.m
+++ tests/OFWideString/OFWideString.m
@@ -7,11 +7,11 @@
  * This file is part of libobjfw. It may be distributed under the terms of the
  * Q Public License 1.0, which can be found in the file LICENSE included in
  * the packaging of this file.
  */
 
-#import <stdio.h>
+#define _ISOC99_SOURCE
 #import <wchar.h>
 
 #import "OFWideString.h"
 
 /* TODO: Do real checks */
@@ -22,11 +22,11 @@
 	OFWideString *s1 = [OFWideString new: L"foo"];
 	OFWideString *s2 = [[OFWideString alloc] init: L""];
 	OFWideString *s3;
 	OFWideString *s4 = [OFWideString new];
 
-	printf("%p\n", [s2 append: L"bar"]);
+	[s2 append: L"bar"];
 	s3 = [s1 clone];
 
 	[s4 setTo: [s2 wcString]];
 
 	wprintf(L"s1 = %S\n", [s1 wcString]);
@@ -34,14 +34,14 @@
 	wprintf(L"s3 = %S\n", [s3 wcString]);
 	wprintf(L"s4 = %S\n", [s4 wcString]);
 
 	[s1 append: [s2 wcString]];
 	wprintf(L"s1 append s2 = %S\n", [s1 wcString]);
-	wprintf(L"strlen(s1) = %zd, [s1 length] = %zd\n",
+	wprintf(L"wcslen(s1) = %zd, [s1 length] = %zd\n",
 	    wcslen([s1 wcString]), [s1 length]);
 	[s1 free];
 	[s2 free];
 	[s3 free];
 	[s4 free];
 
 	return 0;
 }