I have a custom load item function defined for a table. It didn't work when
I expected it to. I spent a lot of time debugging the function and finally
discovered it only works when I do something I didn't expect.
The table does not display anything UNLESS I include calls to MemHandleLock
and MemHandleUnlock. Is there a side effect I don't understand? Could I
have some sort of stack problem? I hate having "magic" code so I'm hopefull
someone can explain.
As far as I can tell, the input to the function and the output from the
function are identical, but it only works if I call MemHandleLock and
MemHandleUnlock.
// snippet
Err CustomLoadItem(VoidPtr table,
Int16 row,
Int16 column,
Boolean editable,
MemHandle *hData,
Int16 *dataOffset,
Int16 *datasize,
FieldPtr fld)
{
*hData = *GetColumn(RecIndexList[row].UniqueID,
column,
dataOffset,
datasize);
// when the following MemHandle calls are commented out, the table does not
display anything
// when they are compiled, the table displays as expected.
MemHandleLock(*hData);
MemHandleUnlock(*hData);
return(0);
}
// end snippet
Thanks,
John Kelsey
www.tacits.com
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