VB/WinAPI, VB and sizeof

VB and sizeof

Author	Message
Timothy Tryzbia #1 / 6	VB and sizeof Is there anything similar to C++'s 'sizeof' function for VB? It seems you can't call this API (since it's not really and API) from VB. I'm trying to find the size of the VB 'FileSystemObject' so that I can move it using memcopy. Any suggestions? Thanks, Tim
Thu, 13 Jun 2002 03:00:00 GMT

Klaus H. Probs #2 / 6	VB and sizeof Timothy, Quote: > Is there anything similar to C++'s 'sizeof' function for VB? It seems you > can't call this API (since it's not really and API) from VB. Use Len(). Quote: > I'm trying to find the size of the VB 'FileSystemObject' so that I can move > it using memcopy. Any suggestions? Um, that's probably not a good idea, unless you really know what you're doing. You do know there's no reference counting when you do that sort of thing, right? Weak references and so on? In any case, you need ObjPtr() to retreive a pointer to the object, and then use MoveMemory (not memcpy -- that doesn't exist in Win32) on that. As most other pointers, this will be 4 bytes in length, since it is a LONG. Good luck ;-) . . . . . . . . . . . . . . . . . . . . . . Please post/reply to the newsgroup(s) Klaus H. Probst, MVP http://www.vbbox.com/ http://www.mvps.org/ccrp/
Fri, 14 Jun 2002 03:00:00 GMT

Kris W. Harney, Jr #3 / 6	VB and sizeof LenB() is probably a safer bet if you are doing API calls or Lsets... Quote: >Timothy, >> Is there anything similar to C++'s 'sizeof' function for VB? It seems you >> can't call this API (since it's not really and API) from VB. >Use Len(). >> I'm trying to find the size of the VB 'FileSystemObject' so that I can move >> it using memcopy. Any suggestions? >Um, that's probably not a good idea, unless you really know what you're doing. >You do know there's no reference counting when you do that sort of thing, right? >Weak references and so on? >In any case, you need ObjPtr() to retreive a pointer to the object, and then use >MoveMemory (not memcpy -- that doesn't exist in Win32) on that. As most other >pointers, this will be 4 bytes in length, since it is a LONG. >Good luck ;-) >. . . . . . . . . . . . . . . . . . . . . . >Please post/reply to the >newsgroup(s) >Klaus H. Probst, MVP > http://www.vbbox.com/ > http://www.mvps.org/ccrp/
Fri, 14 Jun 2002 03:00:00 GMT

Timothy Tryzbia #4 / 6	VB and sizeof Actually I tried both Len and LenB and I get the same error ('object does not support this property'). I agree that it is a bit scary copying the values through memory, but I'm not sure how else to do it. What I need to do is move the FileSystemObject variable from one machine to another (sort of like how you would transfer a file). I know who to move the value of a long or integer, but I know how many bytes they take up so I can use it in my memcopy (or equivalent). Essentially I'm trying to get the FileSystemObject to a remote computer that is not located on a network. How can I transfer the value of a variable from one machine to another (without using ActiveX automation)? Thanks, Tim
Fri, 14 Jun 2002 03:00:00 GMT

Kris W. Harney, Jr #5 / 6	VB and sizeof I'm not too sure if Scripting.FileSystemObject can cross machine boundries... But, I ran a quick test to just pass it around: Private Sub Command1_Click() Dim FS As New FileSystemObject Form2.GetDrives FS End Sub Public Sub GetDrives(ByRef FS As Scripting.FileSystemObject) Dim thing As Variant Label1 = "" Me.Show For Each thing In FS.Drives Label1 = Label1 & " " & thing.DriveLetter Next End Sub This worked fine... You may need to use an UNC to connect to your remote drives. Private Sub Command2_Click() Dim FS As New FileSystemObject FS.CopyFile "\\remotecomputer\share\file.txt", "\\localcomputer\path\file.txt" End Sub This works fine... 'course, I don't know what you are really trying to accomplish, but I hope this helps. -Kris Quote: >Actually I tried both Len and LenB and I get the same error ('object does >not support this property'). I agree that it is a bit scary copying the >values through memory, but I'm not sure how else to do it. What I need to >do is move the FileSystemObject variable from one machine to another (sort >of like how you would transfer a file). I know who to move the value of a >long or integer, but I know how many bytes they take up so I can use it in >my memcopy (or equivalent). >Essentially I'm trying to get the FileSystemObject to a remote computer that >is not located on a network. How can I transfer the value of a variable >from one machine to another (without using ActiveX automation)? >Thanks, >Tim
Sat, 15 Jun 2002 03:00:00 GMT

fred #6 / 6	VB and sizeof Hi You better not try to copy a COM object. What you get in VB when you instantiate an object is a pointer to an interface, in this case a pointer to interface IFileSystem. You can't know how the properties are implemented. They could be private variables or calculated values, the object could infact support other interfaces (like in this case IDispatch). So you can't know how to copy the 'state' of the object using a memory copy. The only thing you can do is copy the memory pointer to the interface into another variable, but this is something you really don't want to do in this case. Hope this helps. bye
Sun, 16 Jun 2002 03:00:00 GMT

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