--- /dev/null
+#ifndef CTYPE_H_
+#define CTYPE_H_
+
+int isalnum(int c);
+int isalpha(int c);
+#define isascii(c) ((c) < 128)
+int isblank(int c);
+int isdigit(int c);
+int isupper(int c);
+int islower(int c);
+int isprint(int c);
+int isspace(int c);
+
+int toupper(int c);
+int tolower(int c);
+
+#endif /* CTYPE_H_ */