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Can FileOpen Return 0?

jaberwacky
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jaberwacky Universalist

jaberwacky

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It says it returns a file "handle".  The lowest handle I've seen is one but that doesn't mean it can't be zero sometimes.  So I was just wondering.  Thanks.

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Blue_Drache Universalist

Blue_Drache

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A return of zero is (usually) reserved for error situations.  That being said, if the handle isn't > 0 then it's returned as null, I believe.

Edited by Blue_Drache

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Edano Universalist

Edano

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Right, so I was just wondering what I should do about a possible zero case.  Could it ever appear?  If so, what does it mean?

.

did it appear or just theoretically ?

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Edano Universalist

Edano

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a quick google search describes a 0 handle as "not valid". so maybe this is reserved for a special error.

this corresponds to what Blue_Drache said

Edited by Edano

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jaberwacky Universalist

jaberwacky

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Ok, so if the handle returned by FileOpen is in harmony with other file handles (you have established this), then why is it in quotes in the helpfile?  What's different about it?

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BrewManNH Universalist

BrewManNH

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It's an internal AutoIt handle, not a Windows handle. Look at what you get from WinGetHandle to see what a real handle looks like.

Edited by BrewManNH

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jaberwacky Universalist

jaberwacky

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Thanks BrewManNH.  I think that answers it. 

Well, maybe not completely but still it answers a lot.

Edited by jaberwocky6669

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guinness Universalist

guinness

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Why would you assume that zero means error?

I can see how someone could think that, considering functions often return 0 on failure. Of course in the instance of FileOpen it's -1.

UDF List:

 
_AdapterConnections() • _AlwaysRun() • _AppMon() • _AppMonEx() • _ArrayFilter/_ArrayReduce • _BinaryBin() • _CheckMsgBox() • _CmdLineRaw() • _ContextMenu() • _ConvertLHWebColor()/_ConvertSHWebColor() • _DesktopDimensions() • _DisplayPassword() • _DotNet_Load()/_DotNet_Unload() • _Fibonacci() • _FileCompare() • _FileCompareContents() • _FileNameByHandle() • _FilePrefix/SRE() • _FindInFile() • _GetBackgroundColor()/_SetBackgroundColor() • _GetConrolID() • _GetCtrlClass() • _GetDirectoryFormat() • _GetDriveMediaType() • _GetFilename()/_GetFilenameExt() • _GetHardwareID() • _GetIP() • _GetIP_Country() • _GetOSLanguage() • _GetSavedSource() • _GetStringSize() • _GetSystemPaths() • _GetURLImage() • _GIFImage() • _GoogleWeather() • _GUICtrlCreateGroup() • _GUICtrlListBox_CreateArray() • _GUICtrlListView_CreateArray() • _GUICtrlListView_SaveCSV() • _GUICtrlListView_SaveHTML() • _GUICtrlListView_SaveTxt() • _GUICtrlListView_SaveXML() • _GUICtrlMenu_Recent() • _GUICtrlMenu_SetItemImage() • _GUICtrlTreeView_CreateArray() • _GUIDisable() • _GUIImageList_SetIconFromHandle() • _GUIRegisterMsg() • _GUISetIcon() • _Icon_Clear()/_Icon_Set() • _IdleTime() • _InetGet() • _InetGetGUI() • _InetGetProgress() • _IPDetails() • _IsFileOlder() • _IsGUID() • _IsHex() • _IsPalindrome() • _IsRegKey() • _IsStringRegExp() • _IsSystemDrive() • _IsUPX() • _IsValidType() • _IsWebColor() • _Language() • _Log() • _MicrosoftInternetConnectivity() • _MSDNDataType() • _PathFull/GetRelative/Split() • _PathSplitEx() • _PrintFromArray() • _ProgressSetMarquee() • _ReDim() • _RockPaperScissors()/_RockPaperScissorsLizardSpock() • _ScrollingCredits • _SelfDelete() • _SelfRename() • _SelfUpdate() • _SendTo() • _ShellAll() • _ShellFile() • _ShellFolder() • _SingletonHWID() • _SingletonPID() • _Startup() • _StringCompact() • _StringIsValid() • _StringRegExpMetaCharacters() • _StringReplaceWholeWord() • _StringStripChars() • _Temperature() • _TrialPeriod() • _UKToUSDate()/_USToUKDate() • _WinAPI_Create_CTL_CODE() • _WinAPI_CreateGUID() • _WMIDateStringToDate()/_DateToWMIDateString() • Au3 script parsing • AutoIt Search • AutoIt3 Portable • AutoIt3WrapperToPragma • AutoItWinGetTitle()/AutoItWinSetTitle() • Coding • DirToHTML5 • FileInstallr • FileReadLastChars() • GeoIP database • GUI - Only Close Button • GUI Examples • GUICtrlDeleteImage() • GUICtrlGetBkColor() • GUICtrlGetStyle() • GUIEvents • GUIGetBkColor() • Int_Parse() & Int_TryParse() • IsISBN() • LockFile() • Mapping CtrlIDs • OOP in AutoIt • ParseHeadersToSciTE() • PasswordValid • PasteBin • Posts Per Day • PreExpand • Protect Globals • Queue() • Resource Update • ResourcesEx • SciTE Jump • Settings INI • SHELLHOOK • Shunting-Yard • Signature Creator • Stack() • Stopwatch() • StringAddLF()/StringStripLF() • StringEOLToCRLF() • VSCROLL • WM_COPYDATA • More Examples...

Updated: 22/04/2018

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jaberwacky Universalist

jaberwacky

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Cool.  I just thought I'd ask because I usually check the return from FileOpen and I never see zero.  So I just wanted to make sure if it was anything special, in this case.

In fact, if I use the following code then the only time I have errors is if I use FileOpen in other places.  I know that this is not correct code that should ever be relied on but it's just a test.

Switch FileOpen($mypath, $FO_READ)
    Case 1
        ; do stuff with the file
        FileClose(1)
EndSwitch
Edited by jaberwocky6669

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jaberwacky Universalist

jaberwacky

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Yes, I know it returns -1 on error but the question I had was this: Does zero have a non-handle but a still special value?  If so, then what?  But I think guinness answered it with saying that zero could be an internal handle.

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guinness Universalist

guinness

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Don't take my word on it, trancexx has seen the core code, I haven't.

UDF List:

 
_AdapterConnections() • _AlwaysRun() • _AppMon() • _AppMonEx() • _ArrayFilter/_ArrayReduce • _BinaryBin() • _CheckMsgBox() • _CmdLineRaw() • _ContextMenu() • _ConvertLHWebColor()/_ConvertSHWebColor() • _DesktopDimensions() • _DisplayPassword() • _DotNet_Load()/_DotNet_Unload() • _Fibonacci() • _FileCompare() • _FileCompareContents() • _FileNameByHandle() • _FilePrefix/SRE() • _FindInFile() • _GetBackgroundColor()/_SetBackgroundColor() • _GetConrolID() • _GetCtrlClass() • _GetDirectoryFormat() • _GetDriveMediaType() • _GetFilename()/_GetFilenameExt() • _GetHardwareID() • _GetIP() • _GetIP_Country() • _GetOSLanguage() • _GetSavedSource() • _GetStringSize() • _GetSystemPaths() • _GetURLImage() • _GIFImage() • _GoogleWeather() • _GUICtrlCreateGroup() • _GUICtrlListBox_CreateArray() • _GUICtrlListView_CreateArray() • _GUICtrlListView_SaveCSV() • _GUICtrlListView_SaveHTML() • _GUICtrlListView_SaveTxt() • _GUICtrlListView_SaveXML() • _GUICtrlMenu_Recent() • _GUICtrlMenu_SetItemImage() • _GUICtrlTreeView_CreateArray() • _GUIDisable() • _GUIImageList_SetIconFromHandle() • _GUIRegisterMsg() • _GUISetIcon() • _Icon_Clear()/_Icon_Set() • _IdleTime() • _InetGet() • _InetGetGUI() • _InetGetProgress() • _IPDetails() • _IsFileOlder() • _IsGUID() • _IsHex() • _IsPalindrome() • _IsRegKey() • _IsStringRegExp() • _IsSystemDrive() • _IsUPX() • _IsValidType() • _IsWebColor() • _Language() • _Log() • _MicrosoftInternetConnectivity() • _MSDNDataType() • _PathFull/GetRelative/Split() • _PathSplitEx() • _PrintFromArray() • _ProgressSetMarquee() • _ReDim() • _RockPaperScissors()/_RockPaperScissorsLizardSpock() • _ScrollingCredits • _SelfDelete() • _SelfRename() • _SelfUpdate() • _SendTo() • _ShellAll() • _ShellFile() • _ShellFolder() • _SingletonHWID() • _SingletonPID() • _Startup() • _StringCompact() • _StringIsValid() • _StringRegExpMetaCharacters() • _StringReplaceWholeWord() • _StringStripChars() • _Temperature() • _TrialPeriod() • _UKToUSDate()/_USToUKDate() • _WinAPI_Create_CTL_CODE() • _WinAPI_CreateGUID() • _WMIDateStringToDate()/_DateToWMIDateString() • Au3 script parsing • AutoIt Search • AutoIt3 Portable • AutoIt3WrapperToPragma • AutoItWinGetTitle()/AutoItWinSetTitle() • Coding • DirToHTML5 • FileInstallr • FileReadLastChars() • GeoIP database • GUI - Only Close Button • GUI Examples • GUICtrlDeleteImage() • GUICtrlGetBkColor() • GUICtrlGetStyle() • GUIEvents • GUIGetBkColor() • Int_Parse() & Int_TryParse() • IsISBN() • LockFile() • Mapping CtrlIDs • OOP in AutoIt • ParseHeadersToSciTE() • PasswordValid • PasteBin • Posts Per Day • PreExpand • Protect Globals • Queue() • Resource Update • ResourcesEx • SciTE Jump • Settings INI • SHELLHOOK • Shunting-Yard • Signature Creator • Stack() • Stopwatch() • StringAddLF()/StringStripLF() • StringEOLToCRLF() • VSCROLL • WM_COPYDATA • More Examples...

Updated: 22/04/2018

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trancexx Universalist

trancexx

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Yes, I know it returns -1 on error but the question I had was this: Does zero have a non-handle but a still special value?  If so, then what?  But I think guinness answered it with saying that zero could be an internal handle.

If there is anything special to any of values returned then it would have been docomented, just as -1 is.

BrewManNH, not guinness. Go get some sleep or do whatever you do when you start not making sense.

♡♡♡

.

eMyvnE

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