$ListAdj

Adjust length of $list item

Note: Most Sirius $functions have been deprecated in favor of Object Oriented methods. There is no OO equivalent for the $ListAdj function as the Stringlist replacement for $lists are natively longstring capable.

This function adjusts the length of a $list item. Generally, this $list would have been created with the $ListNew function.

The $ListAdj function accepts three arguments and returns a numeric result. It is a callable $function.

The first argument is a $list identifier. This is a required argument.

The second argument is a $list item number. This is a required argument.

The third argument is a number that indicates the new length of the $list item. This is a required argument. Its minimum valid value is 0; the maximum value is 6124 under Sirius Mods Version 6.5 and earlier, and it is 2**31-1 under Sirius Mods Version 6.6 and later. If this value is smaller than the current length of the $list item, the $list item is truncated. If this value is larger than the current length of the $list item, the $list item is padded with blanks to the indicated length.

Syntax

[%RESULT =] $ListAdj(list_identifier, itemnum, length)

%result is set to 0 if the new item length is the same as the old item length, 1 if it is less, 2 if it is greater, or a negative number if an error has occurred.

Error codes

-3 - No room to add item (if LISTFC $SirParm parameter not set) All other errors cause request cancellation

Usage notes

• $ListAdj is extremely efficient if the $list item size is not being changed (return value for $ListAdj of 0), fairly efficient when a $list item is being shortened (return value of 1) and can be fairly expensive when a $list item is being lengthened (return value of 2). The latter case can be expensive because such a $ListAdj can result in the splitting of a $list leaf page. Once a leaf page is split, it will not be merged back together, even if subsequent $LISTREMs (or $LISTADJs) makes this possible.

  Because split leaf pages remain split, heavy use of $LISADJ calls that increase $list item size (and $ListIns and $ListRem) can result in "sparse&CQ. $lists which place an unnecessary burden on the buffer pool and CCATEMP. It can also result in an inability to add an item to the end of the $list (via $ListAdd) because of a full pointer page, even though the $list is nowhere near the theoretical capacity for a $list. $List compression can be done using the $List_Copy_Items function.

Example

The following example illustrates how $ListAdj can be used to add an asterisk to the end of a $list item:

%LEN = $ListILn(%LIST, %NUM) %RC = $ListAdj(%LIST, %NUM, %LEN + 1) %RC = $ListOvl(%LIST, %NUM, %LEN + 1, '*')

Products authorizing $ListAdj

• Sirius functions
• Fast/Unload User Language Interface
• Janus Open Client
• Janus Open Server
• Janus Sockets
• Janus Web Server
• Japanese functions
• Sir2000 Field Migration Facility