Exactly, what does -1 mean

[Kalin 0]

In au3, what does the -1 number mean.

It's a number so frequently used in autoit.

Can anyone share with me what it is, what it's used for? < purposes

[MattyD 10]

usually its used to represent a default value. inside the fuction there will be an if statement say:

If $param = -1 Then $Param = $SomeConstant

[Kalin 0]

usually its used to represent a default value. inside the fuction there will be an if statement say:

If $param = -1 Then $Param = $SomeConstant

Can you give more detail please?

Thank you for helping in all, but the value -1 isn't really explained at all in the helpfile.

So I'll need full detail please.

[omikron48 0]

It depends on the context, what -1 may mean.

As a condition parameter, it may mean the number value negative one or just a non-zero value to mean True.

As a Step parameter in a For...Next loop, it means that the loop goes in a decreasing increment of one.

As an @error or @extended value, it may mean whatever the function designer wants it to indicate.

[Kalin 0]

It depends on the context, what -1 may mean.

As a condition parameter, it may mean the number value negative one or just a non-zero value to mean True.

As a Step parameter in a For...Next loop, it means that the loop goes in a decreasing increment of one.

As an @error or @extended value, it may mean whatever the function designer wants it to indicate.

Finally! Someone gave me a answer without thinking I'm trying to be offensive, thank you good sir.

[water 1,872]

As an example please see the help file for GUICreate. -1 means "center" if specified for the "left" or "top" parameter for this function.

-1 might mean something completely different for another function.

Edited September 28, 2010 by water

[MattyD 10]

Ok so lets take say, GUICtrlCreateEdit

GUICtrlCreateEdit ( "text", left, top [, width [, height [, style [, exStyle]]]] )

The default style is:

BitOR($ES_WANTRETURN, $WS_VSCROLL, $WS_HSCROLL, $ES_AUTOVSCROLL, $ES_AUTOHSCROLL)

Lets say I want to keep the default style but set a different parameter for exstyle.

I can write this:

GUICtrlCreateEdit("text", 0, 0, 200, 200, BitOR($ES_WANTRETURN, $WS_VSCROLL, $WS_HSCROLL, $ES_AUTOVSCROLL, $ES_AUTOHSCROLL), $WS_EX_CLIENTEDGE)

Or I can write this:

GUICtrlCreateEdit("text", 0, 0, 200, 200, -1, $WS_EX_CLIENTEDGE)

-1 is not a magic number in autoit. It will only work on functions that specifically are coded to interpret it as a default value. If i wanted my function to interpret "pink elephant" as a default value i could but -1 is probably better .

Edit: Woah lots of posts were made in the mean time

Finally! Someone gave me a answer without thinking I'm trying to be offensive, thank you good sir.

Didn't think that way at all... sorry if thats what it sounded like. Edited September 28, 2010 by MattyD

[Kalin 0]

As an example please see the help file for GUICreate. -1 means "center" if specified for the "left" or "top" parameter for this function.

-1 might mean something completely different for another function.

Awww, I'm this is going to be a hard little code to learn.

So many variations. @_@

Thanks guise!

[Kalin 0]

Ok so lets take say, GUICtrlCreateEdit

GUICtrlCreateEdit ( "text", left, top [, width [, height [, style [, exStyle]]]] )

The default style is:

BitOR($ES_WANTRETURN, $WS_VSCROLL, $WS_HSCROLL, $ES_AUTOVSCROLL, $ES_AUTOHSCROLL)

Lets say I want to keep the default style but set a different parameter for exstyle.

I can write this:

GUICtrlCreateEdit("text", 0, 0, 200, 200, BitOR($ES_WANTRETURN, $WS_VSCROLL, $WS_HSCROLL, $ES_AUTOVSCROLL, $ES_AUTOHSCROLL), $WS_EX_CLIENTEDGE)

Or I can write this:

GUICtrlCreateEdit("text", 0, 0, 200, 200, -1, $WS_EX_CLIENTEDGE)

-1 is not a magic number in autoit. It will only work on functions that specifically are coded to interpret it as a default value. If i wanted my function to interpret "pink elephant" as a default value i could but -1 is probably better .

Thank you, this should be enough for now that I can look into.

If I need any more help with this subject I will be sure to bump this thread.

[omikron48 0]

I also use -1 as a default parameter for some of my functions that also take values 0 to positive infinity. In that particular case, -1 is easier to account for than just any random negative number.

Kinda like a search function that I coded, one of the parameters I use is the search depth or how many folders deep should the search function run. I used 0 to indicate only within the starting folder, any positive number to indicate how many folders deep in particular, then -1 to indicate that the search should go until whatever the deepest folder level is.

Edited September 28, 2010 by omikron48

[Kalin 0]

You all are so awesome.

[Melba23 2,773]

Kalin,

There is another use for -1 when you are addressing controls. If you use -1 in place of the ControlID, it means "use the last created control":

#include <GUIConstantsEx.au3>

$hGUI = GUICreate("Test", 500, 500)

$hLabel_First = GUICtrlCreateLabel("", 10, 10, 100, 20)
GUICtrlSetData(-1, "First") ; <<<<<<<<<<<<<<<<<<

$hLabel_Second = GUICtrlCreateLabel("", 10, 50, 100, 20)
GUICtrlSetData(-1, "Second") ; <<<<<<<<<<<<<<<<<<

GUISetState()

While 1
    Switch GUIGetMsg()
        Case $GUI_EVENT_CLOSE
            Exit
    EndSwitch
WEnd

Saves a lot of wear and tear on the typing fingers if you use long variable names!

M23

[987learner 0]

-1 should be documented in the help file, really.

So many meaning yet no info in help file

[trancexx 921]

-2 too.

[czardas 1,175]

Dim $ambiguity = -2
MsgBox(0, "???", $ambiguity & " = " & 4^.5)

Edited September 28, 2010 by czardas

[Kalin 0]

There are ALOT of things they need to include in the helpfile, hopefully they will be updating it soon.

[Kalin 0]

Dim $ambiguity = -2
MsgBox(0, "???", $ambiguity & " = " & 4^.5)

lol wat...

[MvGulik 86]

There are ALOT of things they need to include in the helpfile, hopefully they will be updating it soon.

Assuming with "They" you mean the volunteers that mainly keep updating/upgrading AutoIt.

Your free in trying to do some preliminary work in the ALOT area if you like.

[Kalin 0]

Assuming with "They" you mean the volunteers that mainly keep updating/upgrading AutoIt.

Your free in trying to do some preliminary work in the ALOT area if you like.

Did I say that I didn't mean "They" so you foreclaim?

God, seriously people, stop trying.

And sounds good to me.

I can help.

[MvGulik 86]

And sounds good to me.

I can help.

Great. Just hope you know what a valik is.