START-FUNCTION

START-FUNCTION

This function selects the current key of reference and positions the file pointer for the next NEXT or PREVIOUS function.

If this function fails, RETURN-CODE is set to zero and the current key of reference is placed in the "undefined" state.

Syntax

SET START-FUNCTION TO TRUE

CALL "I$IO" USING IO-FUNCTION

record

keyNum

keySize

mode

GIVING returnCode

Parameters:

f	must be a valid file handle returned by OPEN-FUNCTION.
record	points to the area to hold the record read.
keyNum	selects which key to use. The value can be 0 or greater than 0, where 0 is the primary key, 1 is the first alternate key and so on. The corresponding key area in record must contain the key value that will be used to position the file.
keySize	indicates the size of the key. If keysize is zero, the entire key is used. Otherwise, only the first keysize bytes of the key will be used.
mode	selects how the file is to be positioned with respect to the key value defined in record. It can be one of the following values (defined in "isfilesys.def"):
	F_EQUALS	The file is positioned at the record that matches the key value.
	F_NOT_LESS	The file is positioned at the record that matches the key value, or the next greater one if no one matches.
	F_GREATER	The file is positioned at the first record greater than the key value specified.
	F_LESS	The file is positioned at the last record smaller than the key value specified.
	F_NOT_GREATER	The file is positioned at the record that matches the key value, or the last record smaller than the key value if no one matches.

Return code:

returnCode can be any signed numeric data item and provides additional information:

>0	Operation successful.
0	Operation failed.