diff --git a/libc/Makefile b/libc/Makefile
index f85516f2..101f5b3f 100644
--- a/libc/Makefile
+++ b/libc/Makefile
@@ -22,6 +22,7 @@ aux/c++.o \
 aux/op-new.o \
 ctype/isalnum.o \
 ctype/isalpha.o \
+ctype/isascii.o \
 ctype/isblank.o \
 ctype/iscntrl.o \
 ctype/isdigit.o \
diff --git a/libc/ctype/isascii.cpp b/libc/ctype/isascii.cpp
new file mode 100644
index 00000000..95fcabbd
--- /dev/null
+++ b/libc/ctype/isascii.cpp
@@ -0,0 +1,30 @@
+/*******************************************************************************
+
+    Copyright(C) Jonas 'Sortie' Termansen 2014.
+
+    This file is part of the Sortix C Library.
+
+    The Sortix C Library is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or (at your
+    option) any later version.
+
+    The Sortix C Library is distributed in the hope that it will be useful, but
+    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
+    License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
+
+    ctype/isascii.cpp
+    Returns whether the character is an ascii character.
+
+*******************************************************************************/
+
+#include <ctype.h>
+
+extern "C" int isascii(int c)
+{
+	return 0 <= c && c < 128 ? 1 : 0;
+}
diff --git a/libc/include/ctype.h b/libc/include/ctype.h
index c9f7ecec..a7dd2dd1 100644
--- a/libc/include/ctype.h
+++ b/libc/include/ctype.h
@@ -1,6 +1,6 @@
 /*******************************************************************************
 
-    Copyright(C) Jonas 'Sortie' Termansen 2011.
+    Copyright(C) Jonas 'Sortie' Termansen 2011, 2014.
 
     This file is part of the Sortix C Library.
 
@@ -22,30 +22,51 @@
 
 *******************************************************************************/
 
-/* TODO: POSIX-1.2008 compliance is only partial */
-
-#ifndef _CTYPE_H
-#define _CTYPE_H 1
+#ifndef INCLUDE_CTYPE_H
+#define INCLUDE_CTYPE_H
 
 #include <sys/cdefs.h>
 
 __BEGIN_DECLS
 
-/* TODO: Declare locale_t and the *_t functions here */
+#ifndef __locale_t_defined
+#define __locale_t_defined
+/* TODO: figure out what this does and typedef it properly. This is just a
+         temporary assignment. */
+typedef int __locale_t;
+typedef __locale_t locale_t;
+#endif
+
 int isalnum(int c);
+/* TODO: isalnum_l */
 int isalpha(int c);
+/* TODO: isalpha_l */
+int isascii(int c);
+/* TODO: isascii_l */
 int isblank(int c);
+/* TODO: isblank_l */
 int iscntrl(int c);
+/* TODO: iscntrl_l */
 int isdigit(int c);
+/* TODO: isdigit_l */
 int isgraph(int c);
+/* TODO: isgraph_l */
 int islower(int c);
+/* TODO: islower_l */
 int isprint(int c);
+/* TODO: isprint_l */
 int ispunct(int c);
+/* TODO: ispunct_l */
 int isspace(int c);
+/* TODO: isspace_l */
 int isupper(int c);
+/* TODO: isupper_l */
 int isxdigit(int c);
+/* TODO: isxdigit_l */
 int tolower(int c);
+/* TODO: tolower_l */
 int toupper(int c);
+/* TODO: toupper_l */
 
 __END_DECLS