Many of the built-in Cicode functions supplied with CitectSCADA return a data value to their calling statement. Mathematical functions return a calculated value. The Date ( ) and Time ( ) functions return the current date and time. Other functions, like PageDisplay ( ), perform an action, and return a value indicating either the success of the action or the type of error that occurred.
You can also use return values in your own functions, to return data to the calling statement. The return value is assigned in the RETURN Statement:
The optional RETURN Statement of a function (if used), needs to be placed in the executable Statements section of a Cicode function between the FUNCTION and END Statements. Because the RETURN Statement is used to return data values that have usually been manipulated by the function, they are usually placed last just before the END Statement.
<ReturnDataType>
FUNCTION
FunctionName ( <Arguments> )
<Statement> ;
<Statement> ;
<Statement> ;
RETURN <ReturnValue> ;
END
The RETURN Statement consists of the RETURN keyword followed by a value to be returned and finished with the semicolon (;) end-of-line marker.
The RETURN value needs to be of the same data type as was declared in the Return Data Type Statement at the start of the function declaration. The return data type of a function can be only one of six possible data types: INT (32 bits), REAL (64 bits), STRING (255 bytes), OBJECT (32 bits), QUALITY or TIMESTAMP (64 bits). If no Return Data Type Statement is declared, the function will not be able to return any type of data.
If the RETURN Statement within the function encounters a different data type to that declared in the Return Data Type Statement, the value is converted to the declared return data type. For information about the Return Data Type Statement, see the section titled Declaring the Return Data Type.
FUNCTION, INT, REAL, STRING, and OBJECT are Cicode keywords and as such, are reserved.
Note: In the following function syntax example every placeholder shown inside arrow brackets ( <placeholder> ) should be replaced in any actual code with the value of the item that it describes. The arrow brackets and the word they contain should not be included in the statement, and are shown here only for your information.
To declare the value that will be returned to the calling code, you need to replace the <ReturnValue> placeholder in the following example with an appropriate data value to match the Return Data Type as declared in the function.
<ReturnDataType>
FUNCTION
FunctionName ( <Arguments> )
<Statement> ;
<Statement> ;
RETURN <ReturnValue> ;
END
The following example returns an integer of value 5:
INT
FUNCTION
FunctionName ( <Arguments> )
<Statement> ;
INT Status = 5;
<Statement> ;
RETURN Status;
END
The RETURN statement passes a value back to the calling procedure (either another function, command or expression). Outside of the function, the return value can be read by the calling statement. For example, it can be used by the caller as a variable (in a command), or animated (in an expression).