diff --git a/objc/runtime.h b/objc/runtime.h
index ed97450..373841b 100644
--- a/objc/runtime.h
+++ b/objc/runtime.h
@@ -330,4 +330,42 @@ static const id self = nil;
 
 #define objc_msgSendSuper(super, op, ...) objc_msg_lookup_super(super, op)((super)->receiver, op, ## __VA_ARGS__)
 
+#define _C_ID       '@'
+#define _C_CLASS    '#'
+#define _C_SEL      ':'
+#define _C_BOOL     'B'
+
+#define _C_CHR      'c'
+#define _C_UCHR     'C'
+#define _C_SHT      's'
+#define _C_USHT     'S'
+#define _C_INT      'i'
+#define _C_UINT     'I'
+#define _C_LNG      'l'
+#define _C_ULNG     'L'
+#define _C_LNG_LNG  'q'
+#define _C_ULNG_LNG 'Q'
+
+#define _C_FLT      'f'
+#define _C_DBL      'd'
+
+#define _C_BFLD     'b'
+#define _C_VOID     'v'
+#define _C_UNDEF    '?'
+#define _C_PTR      '^'
+
+#define _C_CHARPTR  '*'
+#define _C_ATOM     '%'
+
+#define _C_ARY_B    '['
+#define _C_ARY_E    ']'
+#define _C_UNION_B  '('
+#define _C_UNION_E  ')'
+#define _C_STRUCT_B '{'
+#define _C_STRUCT_E '}'
+#define _C_VECTOR   '!'
+
+#define _C_COMPLEX  'j'
+#define _C_CONST    'r'
+
 #endif // __LIBOBJC_RUNTIME_H_INCLUDED__