Re: [PATCH] handle whitespace before %% in scanf

[Rich Felker <dalias@libc.org>]

On Mon, Jul 10, 2017 at 04:44:45PM +0200, Jens Gustedt wrote:
> Hello Bartosz,
> 
> On Mon, 10 Jul 2017 10:22:37 +0200 Bartosz Brachaczek
> <b.brachaczek@gmail.com> wrote:
> 
> > > EXAMPLE 5 The call:
> > > 
> > >     #include <stdio.h>
> > >     /* ... */
> > >     int n, i;
> > >     n = sscanf("foo % bar 42", "foo%%bar%d", &i);
> > > 
> > > will assign to 'n' the value 1 and to 'i' the value 42 because input
> > > white-space characters are skipped for both the '%' and 'd'
> > > conversion specifiers.  
> > 
> > Now, the code in the example is clearly broken, as either the format 
> > string should be "foo%% bar%d" or the input string should be
> > "foo %bar 42", but the explanation does imply that '%%' consumes
> > whitespace.
> 
> Yes, I have noted this as an editorial fix for C17

So you can confirm that it's intentional that %% consume space? That
seems utterly awful but I guess you can use %*1[%] in place of %% to
do what %% should...

Rich