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Just wondering if there is any reason to open and close a dll manually, compared to letting DllCall open/close it for you.

I assume that if you were to make a bunch of dll calls, you'd want to manually open/close so you'd only have to open it once rather than for every call, but is it worth doing?

How do you open/close your dlls?

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If I am going to call a DLL repeatedly (using _IsPressed in a loop is a good example) then I will always open and close the DLL. Why waste CPU cycles opening and closing the DLL each time? From the Help file for _IsPressed:

If calling this function repeatedly, should open 'user32.dll' and pass in handle

The same is true for file opening/closing. The Help file for FileWriteLine is equally specific:

If a filename is given rather than a file handle, the file will be opened and closed during the function call. For parsing large text files this will be much slower than using filehandles


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ArrayMultiColSort ---- Sort arrays on multiple columns
ChooseFileFolder ---- Single and multiple selections from specified path treeview listing
Date_Time_Convert -- Easily convert date/time formats, including the language used
ExtMsgBox --------- A highly customisable replacement for MsgBox
GUIExtender -------- Extend and retract multiple sections within a GUI
GUIFrame ---------- Subdivide GUIs into many adjustable frames
GUIListViewEx ------- Insert, delete, move, drag, sort, edit and colour ListView items
GUITreeViewEx ------ Check/clear parent and child checkboxes in a TreeView
Marquee ----------- Scrolling tickertape GUIs
NoFocusLines ------- Remove the dotted focus lines from buttons, sliders, radios and checkboxes
Notify ------------- Small notifications on the edge of the display
Scrollbars ----------Automatically sized scrollbars with a single command
StringSize ---------- Automatically size controls to fit text
Toast -------------- Small GUIs which pop out of the notification area


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When using dlls that establish a connection which should be persistent throgh multiple DLLCalls, you have to use DLLopen or you would not be able to proceed. Examples are: WinHTTP, MySQL(libmysql), FTP, BASS.dll, ...

The DLLClose is not that important, since you can just leave the DLL opened until termination, then it will be freed automatically.

Edited by ProgAndy

*GERMAN* [note: you are not allowed to remove author / modified info from my UDFs]My UDFs:[_SetImageBinaryToCtrl] [_TaskDialog] [AutoItObject] [Animated GIF (GDI+)] [ClipPut for Image] [FreeImage] [GDI32 UDFs] [GDIPlus Progressbar] [Hotkey-Selector] [Multiline Inputbox] [MySQL without ODBC] [RichEdit UDFs] [SpeechAPI Example] [WinHTTP]UDFs included in AutoIt: FTP_Ex (as FTPEx), _WinAPI_SetLayeredWindowAttributes

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