$ListAdj: Difference between revisions

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<span class="pageSubtitle"><section begin="desc" />Adjust length of $list item<section end="desc" /></span>
<span class="pageSubtitle"><section begin="desc" />Adjust length of $list item<section end="desc" /></span>


<p class="warning">Most Sirius $functions have been deprecated in favor of Object Oriented methods. The OO equivalent for the $ListAdj function is [[to be entered]].</p>
<p class="warning">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.</p>


This function adjusts the length of a $list item. Generally, this $list would have been created with the $ListNew function.  
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 (:hdref refid=callfun.).  
The $ListAdj function accepts three arguments and returns a numeric result. It is a callable $function (see [[Calling Sirius Mods $functions]]).  


The first argument is a $list identifier. This is a required argument.  
The first argument is a $list identifier. This is a required argument.  
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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.
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==
==Syntax==
<p class="syntax"><section begin="syntax" /> [%RESULT =] $ListAdj(list_identifier, itemnum, length)
<p class="syntax"><section begin="syntax" /> [%RESULT =] $ListAdj(list_identifier, itemnum, length)
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</p>
</p>
<p class="caption">%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.</p>
<p class="caption">%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.</p>
<p class="code">  
<p class="code">  
  -3 - No room to add item
  -3 - No room to add item
(if LISTFC $SirParm parameter not set)
        (if LISTFC $SirParm parameter not set)
  All other errors cause request cancellation
  All other errors cause request cancellation
</p>
</p>
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The following example illustrates how $ListAdj can be used to add an asterisk to the end of a $list item:
The following example illustrates how $ListAdj can be used to add an asterisk to the end of a $list item:
<p class="code"> %LEN = $ListILn(%LIST, %NUM)
<p class="code"> %LEN = $ListILn(%LIST, %NUM)
  %RC = $ListAdj(%LIST, %NUM, %LEN + 1)
  %RC = $ListAdj(%LIST, %NUM, %LEN + 1)
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<p class="caption">Products authorizing $ListAdj
<p class="caption">Products authorizing $ListAdj
</p>
</p>


[[Category:$Functions|$ListAdj]]
[[Category:$Functions|$ListAdj]]

Revision as of 13:32, 9 February 2011

<section begin="desc" />Adjust length of $list item<section end="desc" />

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 (see Calling Sirius Mods $functions).

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

<section begin="syntax" /> [%RESULT =] $ListAdj(list_identifier, itemnum, length) <section end="syntax" />

$ListAdj Function

%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.

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

$ListAdj Error Codes


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, '*')


$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, documented in :hdref refid=listcit..

Products authorizing $ListAdj