13.3 DELETE Statement

The DELETE statement deletes a record from a relative file. It takes the following form:

DELETE ([UNIT=]io-unit, REC=r [, ERR=label] [, IOSTAT=i-var])

io-unit
Is an external unit specifier.

r
Is a scalar numeric expression indicating the record number to be deleted.

label
Is the label of the branch target statement that receives control if an error occurs.

i-var
Is a scalar integer variable that is defined as a positive integer if an error occurs and zero if no error occurs.

Rules and Behavior

In a relative file, the DELETE statement deletes the direct access record specified by r. If REC=r is omitted, the current record is deleted. When the direct access record is deleted, any associated variable is set to the next record number.

The DELETE statement logically removes the appropriate record from the specified file by locating the record and marking it as a deleted record. It then frees the position formerly occupied by the deleted record so that a new record can be written at that position.

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Note: You must use the compiler option specifying OpenVMS defaults for READs to detect that a record has been deleted.

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Examples

The following statement deletes the fifth record in the file connected to I/O unit 10:

  DELETE (10, REC=5)

  DELETE (UNIT=9, REC=10, IOSTAT=IOS, ERR=20)

The tenth record in the file connected to unit 9 is deleted. If an error occurs, control is transferred to the statement labeled 20, and a positive integer is stored in the variable IOS.

For More Information:

• On an alternative form for the DELETE statement, see Section B.9.
  
  
• On the UNIT control specifier, see Section 10.2.1.1.
  
  
• On the ERR control specifier, see Section 10.2.1.8.
  
  
• On the IOSTAT control specifier, see Section 10.2.1.7.
  
  
• On the REC control specifier, see Section 10.2.1.4.
  
  
• On compiler options, see your user manual or programmer's guide.