SQL Stored Procedures - getting return value

Starting directly with example:

CREATE PROCEDURE ProcessValue
(
@value int,
@returnValue int OUTPUT
)
AS
BEGIN
/* do calculation and processing and assign the result value to output parameter */
SET @returnValue = value + 5*value

END

The following calling of the procedure shows how to get output parameter.

declare @result int
EXEC ProcessValue 15, @result OUTPUT

Of course this example is pretty simple - only for showing how to use. For such usage the SQL scalar-valued functions are better way.