Re: address@hidden: Re: CVS commit: pkgsrc/devel/m4]

[Joerg Sonnenberger]

On Sat, Jul 28, 2007 at 12:11:24AM +0200, Bruno Haible wrote:
>   - restores the previous flags after calling fseeko. Setting __SNPT
>     means to disable block-aligned reading for *all* future fseek calls,
>     but we need it only for the next one.

Be careful, this breaks the intention. If you reset the flag, you
also have to keep overriding fseek/fseeko, because it will set use the
optimisation again. As discussed in this thread, the critical use
pattern is fflush(stdin) && fseeko(stdin, 0, SEEK_CUR) and the second
fseeko would use the optimisation again. I don't think it is critical in
any way to disable the optimisation, as fflush is supposedly a very rare
operation on stdin and fseeko as well.

Joerg