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Destructive backspace
Message
 
À
10/09/2007 16:53:44
Dragan Nedeljkovich (En ligne)
Now officially retired
Zrenjanin, Serbia
Information générale
Forum:
Visual FoxPro
Catégorie:
Codage, syntaxe et commandes
Divers
Thread ID:
01253507
Message ID:
01253568
Vues:
26
>>>What is the hex for a Destructive backspace?
>>>
>>>Tim
>>
>>0x7F -> 127
>>What is Destructive BackSpace?
>
>The distinction comes from telex (TTY) type of data transmission, where the printed character was forever, i.e. the carriage/printhead couldn't erase anything. The first terminals inherited a lot from this protocol, including a lot of names for control characters (character 7 did physically and literally ring a bell, 10 would force the paper to feed one line, and 13 would cause the carriage to return to the beginning of line). The difference was in the editing capabilities - on paper, deletion would be accomplished by backspacing the head to the left, then printing an overstrike character; on the terminal, the character could have been just erased. So the backspace got a spot in the back row, at the very end of the ASCII table - 127. It moved the cursor (which simulated the carriage) one spot left AND deleted the character on that spot.

Thank you Dragan.
I didn't knew that.
But why Destructive? Isn't BackSpace always destructive, like space when you in OVR mode?
Against Stupidity the Gods themselves Contend in Vain - Johann Christoph Friedrich von Schiller
The only thing normal about database guys is their tables.
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