diff --git a/src/H5PartErrors.h b/src/H5PartErrors.h
index 9e9428a..3e995b1 100644
--- a/src/H5PartErrors.h
+++ b/src/H5PartErrors.h
@@ -15,6 +15,13 @@
 			H5PART_ERR_INVAL, \
 			"Attempting to write to read-only file" );
 
+#define CHECK_READONLY_MODE( f )  \
+	if ( ! f->mode==H5PART_READ ) \
+		return (*_err_handler) ( \
+			_H5Part_get_funcname(), \
+			H5PART_ERR_INVAL, \
+			"Operation is not allowed on writable files." );
+
 #define CHECK_TIMEGROUP( f ) \
 	if ( f->timegroup <= 0 ) \
 		return (*_err_handler) ( \