── VOID ──<sequence number>─┬────────┬────────────────────────────────
└─<text>─┘Explanation
The VOID command deletes a record on a page while the terminal is in page mode. (Refer to Page Mode Operations for more information.) The act of simply erasing records displayed by CANDE, such as by writing over them with new sequence numbers, does not automatically delete those records when transmitted to CANDE. The VOID command must precede all characters on a line and begin in the first column, followed by the sequence number. Any number of blanks, or none at all, may separate the VOID command and the sequence number. When the VOID command is used, <text> is ignored. Therefore the text of the record being voided does not have to be cleared from the screen.
The VOID command deletes only one record at a time and is used while in page mode. It allows the user to continue entering text in page mode without interruption. The DELETE command can be used to delete one record or a group of records at any time. However, using a DELETE command within a page interrupts page mode processing.
The sequence number is assumed to consist of the maximum number of digits allowed for the sequence field of the work file. (Refer to Record Formats for information about the sequence fields of the different file types.) After the VOID or V, CANDE interprets as many consecutive digits as are available, up to the maximum length, as being part of the <sequence number>. This means that if the first digit of the sequence field has been overlaid with a V, CANDE scans the remaining seven digits (for an eight-digit sequence field, such as ALGOL) and continues scanning into the text field for one more digit unless a nonnumeric character is encountered.
In order for CANDE to verify that a voided record is correctly in sequence with other records transmitted on the same screen, the following conditions must be met:
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The sequence numbers of both the preceding and following records must be valid and in correct sequential order with both the voided records and with each other.
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The cursor must be placed beyond the record that follows the voided record before the screen is transmitted.
Note that validation is needed only when it is possible for CANDE to misinterpret the sequence number of the voided record. In cases where there is no ambiguity (that is, the text portion does not begin with a digit, and/or the sequence number has sufficient leading zeros), CANDE deletes the correct record.
Examples
The following examples can each be used to delete the record with the sequence number 1000:
V00001000 THIS IS TEXT V 00001000 THIS IS TEXT V 1000 VOID 1000THIS IS TEXT VOID 000010000 THIS IS TEXT
In the next example, the maximum sequence field allowed is eight digits. Note that digits in the text field immediately follow the sequence field. Because the V overlays a leading zero, the next eight consecutive digits are interpreted by CANDE as being the sequence number of the line to be deleted (although the eighth digit was intended to be part of the text field). As a result, the second line, instead of the first line, is deleted.
Before transmitting the VOID command, the text is as follows:
V00001001ST LINE 000010012ND LINE 000050003RD LINE
After the VOID command is transmitted, the text would be as follows:
000010012ND LINE 000050003RD LINE
