FreeFile

[David]

Group:

I have been trying to learn some of the commands and methods of VB and one

shown was FreeFile which I understand gets the next available file number
to store data.

The following is part of suggested code to play with, but won't execute
because it has a bad file name or number.

Does that mean that the File Name which is a concatenation of a literal
"Test" and Index number were not "Dim"med or perhaps the file number
should havew been a pathway?

Would appreciate any suggestions or comments

David


Private Sub Main()

For MyIndex = 1 To 5 ' Loop 5 times
FileNumber = FreeFile(0) ' Get unused file numbers

Open "Test" & MyIndex For Output _
As #FileNumber
Write #FileNumber, "This is a Sample"
Close #FileNumber
Next MyIndex

End Sub

[Rick Rothstein]

Your code ran fine for me; no error messages.

On a different note, I believe (but am not 100% sure) that the way you are using the
FreeFile could lead to problems when writing large files. FreeFile is only guaranteed to
return an unused file number; it does not guarantee not to reuse already used ones. If say
file number 1 were to become fully available during the say loop number 4, I believe
FreeFile could return 1 during the 4th loop instead of 4.

This didn't happen during my test, but that is my understanding. Perhaps the speed at
which VB closes files is slower than the speed required to open and write, 5 times, the
very short text of your example. As I said, I'm not 100% per cent sure on this so perhaps
someone can support or refute my understanding?

Rick

"David" <walterdw@hal-pc.org> wrote in message news:3b4c8a6f@news.devx.com...
>
> Group:
>
> I have been trying to learn some of the commands and methods of VB and one
>
> shown was FreeFile which I understand gets the next available file number
> to store data.
>
> The following is part of suggested code to play with, but won't execute
> because it has a bad file name or number.
>
> Does that mean that the File Name which is a concatenation of a literal
> "Test" and Index number were not "Dim"med or perhaps the file number
> should havew been a pathway?
>
> Would appreciate any suggestions or comments
>
> David
>
>
> Private Sub Main()
>
> For MyIndex = 1 To 5 ' Loop 5 times
> FileNumber = FreeFile(0) ' Get unused file numbers
>
> Open "Test" & MyIndex For Output _
> As #FileNumber
> Write #FileNumber, "This is a Sample"
> Close #FileNumber
> Next MyIndex
>
> End Sub
>

[Arthur Wood]

David,

The call to FreeFile does not need an Argument:

For MyIndex = 1 To 5 ' Loop 5 times
FileNumber = FreeFile() ' Get unused file numbers

Open "Test" & MyIndex For Output As #FileNumber
Write #FileNumber, "This is a Sample"
Close #FileNumber
Next MyIndex

In addition, you should ALWYS DECLARE all variables used in you code, using
the DIM keyword:

Dim MyIndex as Integer
Dim FileNumber as Long

For MyIndex = 1 To 5 ' Loop 5 times
FileNumber = FreeFile() ' Get unused file numbers

Open "Test" & MyIndex For Output As #FileNumber
Write #FileNumber, "This is a Sample"
Close #FileNumber
Next MyIndex


At the very top of the code module where this is found, you should also add
the line :

Option Explicit

That will FORCE you to declare all varaiblesd BEFORE they are used.

As the code you showed is written, the two variables that you use (MyIndex
and FileNumber) are in fact created as type VARIANT.

Arthur Wood
"David" <walterdw@hal-pc.org> wrote:
>
>Group:
>
>I have been trying to learn some of the commands and methods of VB and one
>
>shown was FreeFile which I understand gets the next available file number
>to store data.
>
>The following is part of suggested code to play with, but won't execute

>because it has a bad file name or number.
>
>Does that mean that the File Name which is a concatenation of a literal
>"Test" and Index number were not "Dim"med or perhaps the file number
>should havew been a pathway?
>
>Would appreciate any suggestions or comments
>
>David
>
>
>Private Sub Main()
>
> For MyIndex = 1 To 5 ' Loop 5 times
> FileNumber = FreeFile(0) ' Get unused file numbers
>
> Open "Test" & MyIndex For Output _
> As #FileNumber
> Write #FileNumber, "This is a Sample"
> Close #FileNumber
> Next MyIndex
>
>End Sub
>

[mrfelis]

Rick Rothstein <rick_newsgroup@email.com> wrote in message
news:3b4c90df@news.devx.com...
> very short text of your example. As I said, I'm not 100% per cent
> sure on this so perhaps
> someone can support or refute my understanding?
>
I was under the same impression, but couldn't be entirely sure. So I wrote
this really cheesy sample to prove one way or the other:

Private Sub Command1_Click()
Text1.Text = FreeFile
Open Text1.Text For Output As #Text1.Text

End Sub


Private Sub Command2_Click()
Close #Text1.Text
End Sub


FreeFile will return the lowest handle available. So if you open files #1 -
5, then Close #2. FreeFile will return 2, then 6.

Also note, successive calls to freefile will return the *same* number until
you open or close another file. So if you are working with 2 or more files
this wil cause an error:

iFile1 = FreeFile
iFile2 = FreeFile
Open "MyFile1" .. As #iFile1
Open "MyFile2" .. As #iFile2

Instead, call free file just before opening the file. Like so:

iFile1 = FreeFile
Open "MyFile1" .. As #iFile1

iFile2 = FreeFile
Open "MyFile2" .. As #iFile2

--
~~~
!ti timda I ,KO
..em deppals nocaeB sivaM
!draH
~~
C'Ya,
mrfelis@yahoo!com

> Rick
>
> "David" <walterdw@hal-pc.org> wrote in message
news:3b4c8a6f@news.devx.com...
> >
> > Group:
> >
> > I have been trying to learn some of the commands and methods of VB and
one
> >
> > shown was FreeFile which I understand gets the next available file
number
> > to store data.
> >
> > The following is part of suggested code to play with, but won't execute
> > because it has a bad file name or number.
> >
> > Does that mean that the File Name which is a concatenation of a literal
> > "Test" and Index number were not "Dim"med or perhaps the file number
> > should havew been a pathway?
> >
> > Would appreciate any suggestions or comments
> >
> > David
> >
> >
> > Private Sub Main()
> >
> > For MyIndex = 1 To 5 ' Loop 5 times
> > FileNumber = FreeFile(0) ' Get unused file
numbers
> >
> > Open "Test" & MyIndex For Output _
> > As #FileNumber
> > Write #FileNumber, "This is a Sample"
> > Close #FileNumber
> > Next MyIndex
> >
> > End Sub
> >
>

[David]

I'm not sure if this allows me to resppnd to an individaul replay, but
I'll see.

To Rick (and others) thanks for taking time. Good points all!, but I think
I
I have something amiss. I took and copied the code (without the recommended

variable declarations and all) onto a different computer that used 95 as
its operating system and a single harddirve, 3 partitions. The program ran
and I could see the text in the files. But when I went back to the
original computer which uses 2000 as the operating system and 3 harddrives
installed to isolate operating systems and utilities, app programs & data
a third disk to isolate net activity, the simple program wouldn't run, again\
with the bad file name or number error message, pathway problem?



"Rick Rothstein" <rick_newsgroup@email.com> wrote:
>Your code ran fine for me; no error messages.
>
>On a different note, I believe (but am not 100% sure) that the way you are
using the
>FreeFile could lead to problems when writing large files. FreeFile is only
guaranteed
>to
>return an unused file number; it does not guarantee not to reuse already
used ones.
>If say
>file number 1 were to become fully available during the say loop number
4, I believe
>FreeFile could return 1 during the 4th loop instead of 4.
>
>This didn't happen during my test, but that is my understanding. Perhaps
the speed at
>which VB closes files is slower than the speed required to open and write,
5 times,
>the
>very short text of your example. As I said, I'm not 100% per cent sure on
this so perhaps
>someone can support or refute my understanding?
>
>Rick
>
>"David" <walterdw@hal-pc.org> wrote in message news:3b4c8a6f@news.devx.com...
>>
>> Group:
>>
>> I have been trying to learn some of the commands and methods of VB and
one
>>
>> shown was FreeFile which I understand gets the next available file number
>> to store data.
>>
>> The following is part of suggested code to play with, but won't execute
>> because it has a bad file name or number.
>>
>> Does that mean that the File Name which is a concatenation of a literal
>> "Test" and Index number were not "Dim"med or perhaps the file number
>> should havew been a pathway?
>>
>> Would appreciate any suggestions or comments
>>
>> David
>>
>>
>> Private Sub Main()
>>
>> For MyIndex = 1 To 5 ' Loop 5 times
>> FileNumber = FreeFile(0) ' Get unused file numbers
>>
>> Open "Test" & MyIndex For Output _
>> As #FileNumber
>> Write #FileNumber, "This is a Sample"
>> Close #FileNumber
>> Next MyIndex
>>
>> End Sub
>>
>

[Rick Rothstein]

As a follow up .... my first test of your code was done on Win98SE using
VB6SP3. I just tried it at my present location and your code ran fine here
too on WinNT4SP6 also using VB6SP3.

Try starting a new project and paste your code into it and run that to see
if you still get the error.

Rick


"David" <walterdw@hal-pc.org> wrote in message
news:3b4cbe8d$1@news.devx.com...
>
> I'm not sure if this allows me to resppnd to an individaul replay, but
> I'll see.
>
> To Rick (and others) thanks for taking time. Good points all!, but I
think
> I
> I have something amiss. I took and copied the code (without the
recommended
>
> variable declarations and all) onto a different computer that used 95 as
> its operating system and a single harddirve, 3 partitions. The program
ran
> and I could see the text in the files. But when I went back to the
> original computer which uses 2000 as the operating system and 3 harddrives
> installed to isolate operating systems and utilities, app programs & data
> a third disk to isolate net activity, the simple program wouldn't run,
again\
> with the bad file name or number error message, pathway problem?
>
>
>
> "Rick Rothstein" <rick_newsgroup@email.com> wrote:
> >Your code ran fine for me; no error messages.
> >
> >On a different note, I believe (but am not 100% sure) that the way you
are
> using the
> >FreeFile could lead to problems when writing large files. FreeFile is
only
> guaranteed
> >to
> >return an unused file number; it does not guarantee not to reuse already
> used ones.
> >If say
> >file number 1 were to become fully available during the say loop number
> 4, I believe
> >FreeFile could return 1 during the 4th loop instead of 4.
> >
> >This didn't happen during my test, but that is my understanding. Perhaps
> the speed at
> >which VB closes files is slower than the speed required to open and
write,
> 5 times,
> >the
> >very short text of your example. As I said, I'm not 100% per cent sure on
> this so perhaps
> >someone can support or refute my understanding?
> >
> >Rick
> >
> >"David" <walterdw@hal-pc.org> wrote in message
news:3b4c8a6f@news.devx.com...
> >>
> >> Group:
> >>
> >> I have been trying to learn some of the commands and methods of VB and
> one
> >>
> >> shown was FreeFile which I understand gets the next available file
number
> >> to store data.
> >>
> >> The following is part of suggested code to play with, but won't execute
> >> because it has a bad file name or number.
> >>
> >> Does that mean that the File Name which is a concatenation of a literal
> >> "Test" and Index number were not "Dim"med or perhaps the file number
> >> should havew been a pathway?
> >>
> >> Would appreciate any suggestions or comments
> >>
> >> David
> >>
> >>
> >> Private Sub Main()
> >>
> >> For MyIndex = 1 To 5 ' Loop 5 times
> >> FileNumber = FreeFile(0) ' Get unused file
numbers
> >>
> >> Open "Test" & MyIndex For Output _
> >> As #FileNumber
> >> Write #FileNumber, "This is a Sample"
> >> Close #FileNumber
> >> Next MyIndex
> >>
> >> End Sub
> >>
> >
>

[Rick Rothstein]

> FreeFile will return the lowest handle available. So if you open files #1 -
> 5, then Close #2. FreeFile will return 2, then 6.

Thanks for the test and confirmation.


> Also note, successive calls to freefile will return the *same* number until
> you open or close another file. So if you are working with 2 or more files
> this wil cause an error:

Which, of course, makes sense since it will return the lowest (thanks to your test above)
currently available file number. Call it twice in a row without using it and it returns
the same, lowest available file number each time (it you didn't use the number it returned
the first time, that number is *still* available for the second function call).


Rick