$ListRep_Lstr
Replace a $list item with a longstring
Note: Many $functions have been deprecated in favor of Object Oriented methods. The OO equivalent for the $ListRep_Lstr function is Replace.
This function replaces an existing $list item with a longstring. Generally, this $list would have been created with the $ListNew function.
The $ListRep_Lstr 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 the item number which is to be replaced. This is a required argument.
The third argument is a string that is to replace the $list item indicated by the second argument. This is a required argument.
Syntax
[%RESULT =] $ListRep_Lstr(list_identifier, item_num, string)
%result is set to 0 if the new item length is the same as the replaced item length, 1 if it is shorter, 2 if it is longer, 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
- $ListRep_Lstr works almost exactly like $ListRep except:
- It accepts a longstring input. $ListRep_Lstr can be used with regular strings as well to pick up automatic request cancellation on programming errors.
- It cancels the request on any errors such as invalid $list identifier or invalid $list item number.
- It does not have an item length argument (argument 4 in $ListRep).
- $ListRep_Lstr is extremely efficient if the $list item size is not being changed (return value for $ListRep_Lstr of 0), fairly efficient when a $list item is being replaced with a shorter string (return value of 1) and can be fairly expensive when a $list item is being replaced with a longer string (return value of 2). The latter case can be expensive because such a $ListRep_Lstr 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 makes this possible. Because of this, heavy use of $LISREP_LSTRs that increase $list item size (and $ListIns and $ListRem) can result in "sparse" $lists which place an unnecessary burden on the buffer pool and CCATEMP. $List compression can be done using the $List_Copy_Items function.