Denso BHT-200QW Spezifikationen PDF herunterladen (Seite 206)

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Description:

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Description:

Creating a user-defined function

FUNCTION...END FUNCTION creates a user-defined function. The function definition

block between FUNCTION and END FUNCTION is a set of some statements and functions.

• You cannot make double definition to a same function name.

• This statement block should not be defined in the block-structured statements (DEF

FN ..END DEF, FOR ..NEXT, FUNCTION ..END FUNCTION,

IF ..THEN ...ELSE ..END IF, SELECT ..CASE ..END SELECT, SUB ..END SUB

and WHILE ..WEND), in the error-handling routine, event-handling routine, or in the

subroutines.

• FUNCTION...END FUNCTION functions can be recursive.

• In defining a string function, you can specify the maximum stringlength. If its

specification is omitted, the default value of 40 characters takes effect.

• dummyparameter, which corresponds to the variable having the same name in the

function definition block, is a local variable valid only in that block. Therefore, if a

variable having the same name as dummyparameter is used outside

FUNCTION...END FUNCTION statement block or used as a dummyparameter of any

other function in the same program, then it will be independently treated.

• In user-defined functions, you can call other user-defined functions. You can nest

FUNCTION...END FUNCTION statements to a maximum of 10 levels.

• When using the FUNCTION...END FUNCTION together with block-structured

statements (DEF FN ..END DEF, FOR ..NEXT, FUNCTION ..END FUNCTION,

IFTHEN ..ELSE ..END IF, SELECT ..CASE ..END SELECT, SUB ..END SUB and

WHILE ..WEND), you can nest them to a maximum of 30 levels.

• If variables other than dummyparameter(s) are specified in the function definition block,

they will be treated as local variables whose current values are avail-able only in that

function definition block, unless PRIVATE or GLOBAL is specified.

• EXIT FUNCTION exits the function block prematurely and returns control to the position

immediately after the statement that called the user-defined function.

• Using Syntax 5 allows you to assign a return value for a user-defined function. The type

of funcname should match that of a return value. If no return value is assigned to

funcname, then the value 0 or a null string will be returned for a numeric function or a

string function, respectively.

Calling a user-defined function

funcname calls the function.

• The number of realparameters should be equal to that of dummyparameters, and

the types of the corresponding variables used in those parameters should be identical.

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