MACROMEDIA COLDFUSION 5-DEVELOPING Develop Manual page 276

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function makes using the structure appears, but the change the function makes
using the directly passed array does not affect the array outside the function.
<CFScript>
</CFScript>
<CFOutput>
<!--- The element one is changed --->
<!--- Element two is unchanged because the function got a copy --->
</CFoutput>
Error handling
You can handle errors in custom functions by writing a status variable indicating
success or failure and some information about the failure. You can also return a
special value to indicate failure. The following sketch outlines possible combinations
of both these approaches:
function bigCalc(x, y, errorInfo)
{
//Create a two-element array inside a structure
mystruct = StructNew();
mystruct.myarray = ArrayNew(1);;
mystruct.myarray[1] = "This is the original element one";
mystruct.myarray[2] = "This is the original element two";
//Define a custom function to manipulate both
//an array in a structure (using struct_param) and
//an array that is passed directly (using array_param).
function setarray( struct_param, array_param )
{
//Change the first element of the array passed in the structure
struct_param.myarray[1] = "This is the NEW element one";
//Change the seond element of the directly-passed array
array_param[2] = "This is the NEW element two";
return "success";
}
//Call the function passing the structure and the array
setarray( mystruct, mystruct.myarray);
<br>#mystruct.myarray[1]#
<br>#mystruct.myarray[2]#
// Clear error state
// This allows errorInfo struct to be reused
structClear(errorInfo);
var isOK = true;
// Do work, populate fields in errorInfo such as
// errorNumber, errorMsg, errorDetail, whatever
...
if (isOK)
{
return calculatedValue;
Chapter 13 Extending ColdFusion Pages with CFML Scripting