Update documentation/source/readme/C Coding Style Guide.rst

documentation/source/readme/C Coding Style Guide.rst

@@ -89,6 +89,7 @@ Rule 1.1 Name identifiers in camel case style.
 +-----------------------------------+-----------------------------------+
 
 .. note:: 
+
    * The ``constant`` in the above table refers to the variable of the basic data type, enumeration, and string type of the const modifier under the global scope, excluding array, struct and union.
    * The ``variable`` in the above table refers to variables other than the constant definition, all using lowercase.