Error in egcs FORTRAN I/O?

[Toon Moene]

I asked:

 > A complete Fortran program showing the problem would be nice too.

And you replied:

>  I would send it, but it is rather large and not that easy
>  to build; moreover, it takes probably an hour of runtime
>  to get to this problem. This is why I'm suggesting to
>  look into the details myself... Or maybe someone have
>  encouuntered a similar problem and patch already exists...

Hmm, yeah, I see - that makes my previous questions also rather  
unhelpfull, as we can't rerun your program that way.

Perhaps some other remarks and questions can help us out:

1. Is the point at which the error is provoked the first
   time through this read statement ?

2. Or is it the first time I/O is done on unit 10 ?

As far as I can see from the libI77 part of the g77 (and f2c)  
runtime library, the function that f__doed points to is probably  
rd_ed (file rdfmt.c), because you're reading a formatted file using  
an `edit string' (I4); it indeed does an fseek (sometimes), and it  
returns errno (why n is still 0 is also not clear to me).

However, I don't see why fseek should fail on unit 10.  Normally,  
unit 10 is either opened by an explicit OPEN statement, or by the  
first I/O on that unit (in which case a file with name `fort.10' is  
opened).  The only way you can get a non-seekable file that way is  
having a named pipe `fort.10' before starting your program.   
However, at open time it is determined whether the file can be  
seeked [sic] (member `useek' of the file unit structure that libI77  
uses internally).  This member is checked before the seek in rd_ed  
is done.

Therefore, I highly suspect one of the underlying components of  
your system (libc or the kernel itself) being at fault here.

I am sorry I cannot help you further.

Toon.