READT Statement

The READT statement reads the next record (block) on the magnetic tape or floppy disk unit, assigning its value to the specified variable.

Format

READT var [RETURNING var]

[THEN

statements

END] [ELSE

statements

END]

Parameter(s)

var	Variable into which the next record is read, in dynamic array form.
RETURNING var	If a tape or floppy disk error occurs while using the RETURNING clause, the tape or floppy disk error is assigned to the returning variable and program control continues through the ELSE clause.
THEN statements	Executes statements if record is successfully read.
ELSE statements	Executes statements if record cannot be read.

Description

The READT statement may be used to read a record from an attached tape or floppy disk unit. If a record is read, its value is assigned to the specified variable and the THEN statements are executed. If the record cannot be read, the ELSE statements are executed, and the value of var1 does not change.

A record might not be read because the tape or floppy disk has not been attached, or because an End-Of-File mark was encountered. To determine why a tape or floppy disk could not be read, the SYSTEM function is often used in the ELSE portion of a READT statement. See SYSTEM Function for more information.

READT also has an optional UNLABELED clause to allow 1/2-inch tapes to read a tape without reading a label.

Format

READT var [UNLABELED] [RETURNING var]

[THEN

statements

END] ELSE

Statements

END

To read tapes or floppy disks in ASCII hexadecimal format, use the READTX statement.

See READTX Statement for more information.

Example

The program segment in this example reads data off a tape and prints them in a readable format. The item-IDs are printed and then each attribute is printed on a separate line, preceded by the attribute number.

LOOP

READT NEWRECORD ELSE

IF SYSTEM(0) = 2 THEN

END.OF.TAPE = TRUE

END ELSE

PRINT "SYSTEM ERROR --"

GOSUB EXIT

END

REC.NUM += 1

UNTIL END.OF.TAPE DO

PRINT "PRESS ANY KEY TO READ RECORD " : REC.NUM :" : " :

INPUT CHAR,1

NO.OF.ATTRS = DCOUNT(NEWRECORD , AM)

FOR I = 1 TO NO.OF.ATTRS

PRINT I, NEWRECORD< I >

NEXT I

REPEAT