diff --git a/libopenjpeg/jp2.h b/libopenjpeg/jp2.h
index 299215e0..1de72a9b 100644
--- a/libopenjpeg/jp2.h
+++ b/libopenjpeg/jp2.h
@@ -77,14 +77,14 @@ typedef enum
 	JP2_STATE_HEADER		= 0x4,
 	JP2_STATE_CODESTREAM	= 0x8,
 	JP2_STATE_END_CODESTREAM	= 0x10,
-	JP2_STATE_UNKNOWN		= 0x80000000
+	JP2_STATE_UNKNOWN		= 0x7fffffff /* ISO C restricts enumerator values to range of 'int' */
 }
 JP2_STATE;
 
 typedef enum
 {
 	JP2_IMG_STATE_NONE			= 0x0,
-	JP2_IMG_STATE_UNKNOWN		= 0x80000000
+	JP2_IMG_STATE_UNKNOWN		= 0x7fffffff
 }
 JP2_IMG_STATE;
 
diff --git a/libopenjpeg/mct.h b/libopenjpeg/mct.h
index c701280a..fab28d0c 100644
--- a/libopenjpeg/mct.h
+++ b/libopenjpeg/mct.h
@@ -93,15 +93,15 @@ double mct_getnorm_real(int compno);
 
 
 opj_bool mct_encode_custom(
-					   // MCT data
+					   /* MCT data */
 					   OPJ_BYTE * p_coding_data,
-					   // size of components
+					   /* size of components */
 					   OPJ_UINT32 n,
-					   // components
+					   /* components */
 					   OPJ_BYTE ** p_data,
-					   // nb of components (i.e. size of p_data)
+					   /* nb of components (i.e. size of p_data) */
 					   OPJ_UINT32 p_nb_comp,
-					   // tells if the data is signed
+					   /* tells if the data is signed */
 					   OPJ_UINT32 is_signed);
 
 opj_bool mct_decode_custom(