import std.stream;


void main()
{
Stream ins = new BufferedFile(__FILE__, FileMode.In);
assert(ins.seekable);

ulong spot = ins.position-1;
printf("peek \"%.*s\"\n", ins.readLine());
ins.seek(spot, SeekPos.Set);
ins.position = spot;
}


/*
what's wrong with this program????
compiles fine, asserts work.

when run prints:
---
peek "import std.stream;"
Error: unable to move file pointer
---

It appears that BufferedFile is seekable (the assert at least claims it is) but when I try to seek on it, the seek fails. */

In article <dcum8v$1ihb$1@digitaldaemon.com>, BCS says...
>
>import std.stream;
>
>
>void main()
>{
>Stream ins = new BufferedFile(__FILE__, FileMode.In);
>assert(ins.seekable);
>
>ulong spot = ins.position-1;
>printf("peek \"%.*s\"\n", ins.readLine());
>ins.seek(spot, SeekPos.Set);
>ins.position = spot;
>}
>
>
>/*
>what's wrong with this program????
>compiles fine, asserts work.
>
>when run prints:
>---
>peek "import std.stream;"
>Error: unable to move file pointer
>---
>
>It appears that BufferedFile is seekable (the assert at least claims it is) but when I try to seek on it, the seek fails. */

I can't reproduce the error on either Windows or Linux using dmd.128 - can you
give more details about your setup?
Another odd detail is that I would expect to be able to reproduce it since you
are asking to set the file pointer to pos = -1. The reason is that when you
create a new BufferedFile the position is at 0 and so position-1 is -1. Then the
code reads a line and tries to set the position to -1 cast to a ulong which is
far outside the range of the actual file data. I'd have to look up the doc for
each platform to see what happens when you try to do that.
-Ben

On Fri, 5 Aug 2005 03:26:23 +0000 (UTC), BCS wrote:

> import std.stream;
> 
> void main()
> {
> Stream ins = new BufferedFile(__FILE__, FileMode.In);
> assert(ins.seekable);
> 
> ulong spot = ins.position-1;
> printf("peek \"%.*s\"\n", ins.readLine());
> ins.seek(spot, SeekPos.Set);
> ins.position = spot;
> }
> 
> /*
> what's wrong with this program????
> compiles fine, asserts work.
> 
> when run prints:
> ---
> peek "import std.stream;"
> Error: unable to move file pointer
> ---
> 
> It appears that BufferedFile is seekable (the assert at least claims it is) but when I try to seek on it, the seek fails. */

You are trying to set the file position to -1. The first position is zero though.

-- 
Derek
Melbourne, Australia
5/08/2005 3:28:40 PM

On Fri, 5 Aug 2005 03:48:22 +0000 (UTC), Ben Hinkle wrote:

> In article <dcum8v$1ihb$1@digitaldaemon.com>, BCS says...

[snip]
> I can't reproduce the error on either Windows or Linux using dmd.128

It failed for me using Windows XP and DMD 0.128

-- 
Derek
Melbourne, Australia
5/08/2005 3:32:03 PM

>> I can't reproduce the error on either Windows or Linux using dmd.128
>
> It failed for me using Windows XP and DMD 0.128

OK - I got it now. I reset my dmd setup and was able to reproduce it. My phobos.lib was in a bad state.