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OS_Find &4F

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  OS_Find &4F Paul Stewart <phorefaux@gmail.com> - 2026-02-21 23:08 +0000
    Re: OS_Find &4F Jean-Michel <jmc.bruck@orange.fr> - 2026-02-22 10:17 +0100
      Re: OS_Find &4F Martin <News04@avisoft.f9.co.uk> - 2026-02-22 10:14 +0000
        Re: OS_Find &4F Steve Fryatt <news@stevefryatt.org.uk> - 2026-02-22 16:33 +0000
        Re: OS_Find &4F Paul Stewart <phorefaux@gmail.com> - 2026-02-22 17:17 +0000
          Re: OS_Find &4F Harriet Bazley <harriet@bazleyfamily.co.uk> - 2026-02-22 21:17 +0000
            Re: OS_Find &4F Paul Stewart <phorefaux@gmail.com> - 2026-02-23 21:02 +0000
              Re: OS_Find &4F Steve Fryatt <news@stevefryatt.org.uk> - 2026-02-23 21:43 +0000
                Re: OS_Find &4F Paul Stewart <phorefaux@gmail.com> - 2026-03-11 10:26 +0000
          Re: OS_Find &4F Steve Fryatt <news@stevefryatt.org.uk> - 2026-02-22 22:54 +0000
            Re: OS_Find &4F Paul Stewart <phorefaux@gmail.com> - 2026-03-11 10:25 +0000

#6592 — OS_Find &4F

Hi there,

Trying to read a log file when the file is already open by the the utility 
that is create it.(downloading a file using WGet and reading the log file 
to display percentage downloaded)

Using SYS "XOS_Find",&4F,file$ TO handle%

Now the above works fine on my RO4.42 and RO5 devices.

When I test with VRPC with RO4 and RO6, Error is generated: Handle is 
either illegal or has been closed and errors with the line number the 
above SYS command is on.

I'm doing
OS_Find command to open the file
getting the size
OS_GBPB to read into buffer
OS_Find to then close the file.

Above all works fine on 4.42 and 5, but generates the Handle is either 
illegal or has been closed error on RO4 and RO6.

Any ideas as to why the RO4 and RO6 do not like SYS "XOS_Find",&4F,file$ 
TO handle% with a file that is already open and being updated, where as 
other OS's are fine with it?

-- 
Paul Stewart
Sent from A9home running RISC OS 4.42

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#6593

In message <b171d8ae5c.Paul@phorefaux>
          Paul Stewart <phorefaux@gmail.com> wrote:

> Hi there,

> Trying to read a log file when the file is already open by the the utility
> that is create it.(downloading a file using WGet and reading the log file
> to display percentage downloaded)

> Using SYS "XOS_Find",&4F,file$ TO handle%

> Now the above works fine on my RO4.42 and RO5 devices.

> When I test with VRPC with RO4 and RO6, Error is generated: Handle is
> either illegal or has been closed and errors with the line number the
> above SYS command is on.

> I'm doing
> OS_Find command to open the file
> getting the size
> OS_GBPB to read into buffer
> OS_Find to then close the file.

> Above all works fine on 4.42 and 5, but generates the Handle is either
> illegal or has been closed error on RO4 and RO6.

> Any ideas as to why the RO4 and RO6 do not like SYS "XOS_Find",&4F,file$
> TO handle% with a file that is already open and being updated, where as
> other OS's are fine with it?

Not sure, but osfind must have evolved
According to OSLib's SHelp manual, there are 32bit handles, the old ones 
were 8bit. from version 6.3 the handles are 32 bits. I don't know how to 
distinguish with Sys "OSfind" on Ro4  ?

You can display handle% for comparison. (Reporter is fine!)
-- 
Jean-Michel

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#6594

In article <2b3b10af5c.jmb@jmc.bruck.orange.fr>,
   Jean-Michel <jmc.bruck@orange.fr> wrote:
> In message <b171d8ae5c.Paul@phorefaux>
>           Paul Stewart <phorefaux@gmail.com> wrote:

> > Hi there,

> > Trying to read a log file when the file is already open by the
> > the utility that is create it.(downloading a file using WGet and
> > reading the log file to display percentage downloaded)

> > Using SYS "XOS_Find",&4F,file$ TO handle%

> > Now the above works fine on my RO4.42 and RO5 devices.

> > When I test with VRPC with RO4 and RO6, Error is generated:
> > Handle is either illegal or has been closed and errors with the
> > line number the above SYS command is on.

> > I'm doing
> > OS_Find command to open the file
> > getting the size
> > OS_GBPB to read into buffer
> > OS_Find to then close the file.

> > Above all works fine on 4.42 and 5, but generates the Handle is
> > either illegal or has been closed error on RO4 and RO6.

> > Any ideas as to why the RO4 and RO6 do not like SYS
> > "XOS_Find",&4F,file$ TO handle% with a file that is already open
> > and being updated, where as other OS's are fine with it?

> Not sure, but osfind must have evolved According to OSLib's SHelp
> manual, there are 32bit handles, the old ones were 8bit. from
> version 6.3 the handles are 32 bits. I don't know how to
> distinguish with Sys "OSfind" on Ro4  ?

> You can display handle% for comparison. (Reporter is fine!)

I suspect the differences are more to do with the FileSystem being
used, rather than the RISC OS version. I have certainly seen
differences in what can be done to open files on different file
systems.

-- 
Martin Avison 
Note that unfortunately this email address will become invalid
without notice if (when) any spam is received. 

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#6595

On 22 Feb, Martin wrote in message
    <5caf1565f8News04@avisoft.f9.co.uk>:

> I suspect the differences are more to do with the FileSystem being used,
> rather than the RISC OS version. I have certainly seen differences in what
> can be done to open files on different file systems.

Indeed.  Assuming that 4.42 and 5.xx are not running on VRPC, I would
suggest that it's worth checking whether VRPC's HostFS is happy to allow two
clients to access the same file at the same time (where HostFS will probably
just be passing on what Windows does by default).

-- 
Steve Fryatt - Leeds, England

http://www.stevefryatt.org.uk/

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#6596

In message <5caf1565f8News04@avisoft.f9.co.uk>
          Martin <News04@avisoft.f9.co.uk> wrote:

> In article <2b3b10af5c.jmb@jmc.bruck.orange.fr>,
>    Jean-Michel <jmc.bruck@orange.fr> wrote:
>> In message <b171d8ae5c.Paul@phorefaux>
>>           Paul Stewart <phorefaux@gmail.com> wrote:

>>> Hi there,

>>> Trying to read a log file when the file is already open by the
>>> the utility that is create it.(downloading a file using WGet and
>>> reading the log file to display percentage downloaded)

>>> Using SYS "XOS_Find",&4F,file$ TO handle%

>>> Now the above works fine on my RO4.42 and RO5 devices.

>>> When I test with VRPC with RO4 and RO6, Error is generated:
>>> Handle is either illegal or has been closed and errors with the
>>> line number the above SYS command is on.

>>> I'm doing
>>> OS_Find command to open the file
>>> getting the size
>>> OS_GBPB to read into buffer
>>> OS_Find to then close the file.

>>> Above all works fine on 4.42 and 5, but generates the Handle is
>>> either illegal or has been closed error on RO4 and RO6.

>>> Any ideas as to why the RO4 and RO6 do not like SYS
>>> "XOS_Find",&4F,file$ TO handle% with a file that is already open
>>> and being updated, where as other OS's are fine with it?

>> Not sure, but osfind must have evolved According to OSLib's SHelp
>> manual, there are 32bit handles, the old ones were 8bit. from
>> version 6.3 the handles are 32 bits. I don't know how to
>> distinguish with Sys "OSfind" on Ro4  ?

>> You can display handle% for comparison. (Reporter is fine!)

> I suspect the differences are more to do with the FileSystem being
> used, rather than the RISC OS version. I have certainly seen
> differences in what can be done to open files on different file
> systems.

Good shout, that had crossed my mind.
In all cases, the file is being read from Wimp$ScrapDir.
On RO4.39, this is set to Memphis, as is the case on RO4/6 (or so I was 
thinking, however, now having checked this, I see I was wrong, it was set 
to !Scrap folder in Resources on HostFS, if I set to Memphis, works as 
expected.  On further testing.  Reading the file works fine with Memphis, 
but errors with IDEFS, HOSTS,ADFS(VRPC),SDFS.

Therefore my next question.
I am using webget and outputting the log file to scrap.  I am trying to 
update a window with percentage of file downloaded, which as I now know 
works fine with Memphis, but not anything else :(.  The file itself is 
open by webget as it is updating it.  I also need to open it for reading 
so I can get the download percentage.

With OS_Find not working apart from on Memphis, is there another way to do 
this?

-- 
Paul Stewart
Sent from A9home running RISC OS 4.42

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#6597

On 22 Feb 2026 as I do recall,
          Paul Stewart  wrote:

[snip]

> I am using webget and outputting the log file to scrap.  I am trying to 
> update a window with percentage of file downloaded, which as I now know 
> works fine with Memphis, but not anything else :(.  The file itself is 
> open by webget as it is updating it.  I also need to open it for reading 
> so I can get the download percentage.
> 
> With OS_Find not working apart from on Memphis, is there another way to do 
> this?
>

What happens if you use OS_File 255 (Load File) instead of OS_Find?


-- 
Harriet Bazley                     ==  Loyaulte me lie ==

Mate, this parrot wouldn't VOOM if you put four million volts through it!

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#6605

In message <3a2352af5c.harriet@bazleyfamily.co.uk>
          Harriet Bazley <harriet@bazleyfamily.co.uk> wrote:

> On 22 Feb 2026 as I do recall,
>           Paul Stewart  wrote:

> [snip]

>> I am using webget and outputting the log file to scrap.  I am trying to
>> update a window with percentage of file downloaded, which as I now know
>> works fine with Memphis, but not anything else :(.  The file itself is
>> open by webget as it is updating it.  I also need to open it for reading
>> so I can get the download percentage.
>> 
>> With OS_Find not working apart from on Memphis, is there another way to do
>> this?
>>

> What happens if you use OS_File 255 (Load File) instead of OS_Find?

Same issue,  reports file is aleady open.

I will dig into Steve Fryatt's suggestion of using PipeFS.
Would appear to be a lot of hassle just to display a download percentage, 
but would like to indicate how far through the download WGet is.  And it's 
a learning curve!

-- 
Paul Stewart
Sent from A9home running RISC OS 4.42

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#6606

On 23 Feb, Paul Stewart wrote in message
    <1e8bd4af5c.Paul@phorefaux>:

> I will dig into Steve Fryatt's suggestion of using PipeFS. Would appear to
> be a lot of hassle just to display a download percentage,

Why is it "a lot of hassle"?

I assume that you're doing something like

  wget <stuff> -o <some-temporary-logfile-name>

to generate your logfile. Instead of that, just do

  wget <stuff> -o pipe:$.YourAppName

and then try to open that same file using OS_Find. Calling it "YourAppName"
(where that's the actual name that you've registered with ROOL for the
application) is a way to minimise the risk that someone else will also be
trying to use the same filename at the same time.

-- 
Steve Fryatt - Leeds, England

http://www.stevefryatt.org.uk/

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#6611

In message <mpro.taxlnn00tiska0e9q.news@stevefryatt.org.uk>
          Steve Fryatt <news@stevefryatt.org.uk> wrote:

>> I will dig into Steve Fryatt's suggestion of using PipeFS. Would appear to
>> be a lot of hassle just to display a download percentage,

> Why is it "a lot of hassle"?

Poor choice of words on my part.

-- 
Paul Stewart
Sent from A9home running RISC OS 4.42

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#6598

On 22 Feb, Paul Stewart wrote in message
    <97283caf5c.Paul@phorefaux>:

> Therefore my next question. I am using webget and outputting the log file
> to scrap.  I am trying to update a window with percentage of file
> downloaded, which as I now know works fine with Memphis, but not anything
> else :(.  The file itself is open by webget as it is updating it.  I also
> need to open it for reading so I can get the download percentage.
> 
> With OS_Find not working apart from on Memphis, is there another way to do
> this?

Would using PipeFS solve the problem? That has been in the OS since
RISC OS 3, and is intended to allow for inter-task file transfer.

I've used it in PrintPDF for communicating with TaskWindow-based tasks, but
not in quite this way. I would assume (but haven't checked) that it would
allow reading from a file that something else was writing to, because that
feels like a significant part of its purpose.

-- 
Steve Fryatt - Leeds, England

http://www.stevefryatt.org.uk/

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#6610

In message <mpro.tavube00gpoog1f85.news@stevefryatt.org.uk>
          Steve Fryatt <news@stevefryatt.org.uk> wrote:

> On 22 Feb, Paul Stewart wrote in message
>     <97283caf5c.Paul@phorefaux>:

>> Therefore my next question. I am using webget and outputting the log file
>> to scrap.  I am trying to update a window with percentage of file
>> downloaded, which as I now know works fine with Memphis, but not anything
>> else :(.  The file itself is open by webget as it is updating it.  I also
>> need to open it for reading so I can get the download percentage.
>> 
>> With OS_Find not working apart from on Memphis, is there another way to do
>> this?

> Would using PipeFS solve the problem? That has been in the OS since
> RISC OS 3, and is intended to allow for inter-task file transfer.

> I've used it in PrintPDF for communicating with TaskWindow-based tasks, but
> not in quite this way. I would assume (but haven't checked) that it would
> allow reading from a file that something else was writing to, because that
> feels like a significant part of its purpose.

Run into same issue with PipeFS, with added bonus if it blocking when pipe 
gets full.  Everyday is a learning day :)

-- 
Paul Stewart
Sent from A9home running RISC OS 4.42

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