Introduction MTB Statements File System Compiler Applications Reference Guide Index

Language Structure Data Division I/O Format Division Procedure Division Mnemonics

PREV function

Syntax: PREV(lun [,EXCP=statement-label])
Discussion: The PREV function returns the value of the key immediately previous to the current file pointer file attached to the specified logical unit number. This feature provides a method for a program to read backwards through a keyed file. (See the FILE statement for another method to read backwards through a keyed file.)

The PREV function does not move the record pointer in the file. To move the record pointer, you must use input/output statements such as READ and WRITE.

Other file-related functions: FIRST, KEY, LAST.

Example: 
VALUE$ = PREV(1)  ! Get previous key in logical unit number 1