Re: Building CVS HEAD libtool outside of source directory

[Bob Friesenhahn]

On Fri, 19 Oct 2007, Eric Blake wrote:

> According to Bob Friesenhahn on 10/19/2007 10:15 AM:
> > % ls -l configure
> > -rwxr-xr-x  1 bfriesen  home  28205 Oct 19 10:57 configure*
>
> There is a known bug in m4 1.4.10 on platforms where fopen(..., "a+")
> opens at the tail of a file, rather than the head.  It looks like this is
> what is biting you.

Facinating.  I would expect opening for append to open at the tail 
(end) of the file although I find your use of 'head' and 'tail' to be 
confusing since a file is not a queue.  From the Solaris manual page:

     a+ or ab+ or a+b    Append; open or create file for  update,
                         writing at end-of-file.

and from the FreeBSD manual page:

     ``a+''  Open for reading and writing.  The file is created if it does not
             exist.  The stream is positioned at the end of the file.  Subse-
             quent writes to the file will always end up at the then current
             end of file, irrespective of any intervening fseek(3) or similar.

OS-X's man page says the same since it borrows from FreeBSD.

It sounds like your code is fighting against the intentions of "a+" 
and that the seek in your referenced patch will be ignored by FreeBSD 
and OS X and should probably be ignored by Solaris as well.

Maybe freopen() can help?

Bob
==== 
Bob Friesenhahn
address@hidden, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/