Index: src/OFMutableString.m
==================================================================
--- src/OFMutableString.m
+++ src/OFMutableString.m
@@ -237,12 +237,11 @@
 	if (fmt == nil)
 		@throw [OFInvalidArgumentException newWithClass: isa
 						       selector: _cmd];
 
 	if ((len = of_vasprintf(&t, [fmt cString], args)) == -1)
-		@throw [OFInvalidArgumentException newWithClass: isa
-						       selector: _cmd];
+		@throw [OFInvalidFormatException newWithClass: isa];
 
 	@try {
 		[self appendCString: t
 			 withLength: len];
 	} @finally {

Index: src/OFStream.m
==================================================================
--- src/OFStream.m
+++ src/OFStream.m
@@ -684,12 +684,11 @@
 	if (fmt == nil)
 		@throw [OFInvalidArgumentException newWithClass: isa
 						       selector: _cmd];
 
 	if ((len = of_vasprintf(&t, [fmt cString], args)) == -1)
-		@throw [OFInvalidArgumentException newWithClass: isa
-						       selector: _cmd];
+		@throw [OFInvalidFormatException newWithClass: isa];
 
 	@try {
 		return [self writeNBytes: len
 			      fromBuffer: t];
 	} @finally {

Index: src/OFString.m
==================================================================
--- src/OFString.m
+++ src/OFString.m
@@ -486,12 +486,11 @@
 		if (fmt == nil)
 			@throw [OFInvalidArgumentException newWithClass: isa
 							       selector: _cmd];
 
 		if ((len = of_vasprintf(&string, [fmt cString], args)) == -1)
-			@throw [OFInvalidArgumentException newWithClass: isa
-							       selector: _cmd];
+			@throw [OFInvalidFormatException newWithClass: isa];
 
 		@try {
 			length = len;
 
 			switch (of_string_check_utf8(string, length)) {

Index: src/of_asprintf.m
==================================================================
--- src/of_asprintf.m
+++ src/of_asprintf.m
@@ -251,12 +251,12 @@
 				    [[obj description] cString]);
 			else
 				if (!append_str(ctx, "(nil)", 5))
 					return false;
 		} @catch (id e) {
-			[e release];
-			return false;
+			free(ctx->buf);
+			@throw e;
 		} @finally {
 			[pool release];
 		}
 
 		break;
@@ -486,21 +486,17 @@
 	if ((ctx.buf = malloc(1)) == NULL)
 		return -1;
 
 	for (ctx.i = 0; ctx.i < ctx.fmt_len; ctx.i++) {
 		if (!states[ctx.state](&ctx)) {
-			if (ctx.buf != NULL)
-				free(ctx.buf);
-
+			free(ctx.buf);
 			return -1;
 		}
 	}
 
 	if (ctx.state != STATE_STRING) {
-		if (ctx.buf != NULL)
-			free(ctx.buf);
-
+		free(ctx.buf);
 		return -1;
 	}
 
 	if (!append_str(&ctx, ctx.fmt + ctx.last, ctx.fmt_len - ctx.last)) {
 		free(ctx.buf);