Re: [musl] print does not support variable width plus padding

[Andrew Snyder <arsnyder16@gmail.com>]

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I did attempt to create my issue with a simple example and was unable, but
I haven’t had time to revisit yet.  Once I get time I will try to isolate.
Could be emscripten related I am just not sure at the point we are also
using varg version of printf


On Wed, Dec 15, 2021 at 4:40 PM enh <enh@google.com> wrote:

> On Wed, Dec 15, 2021 at 1:21 PM Rich Felker <dalias@libc.org> wrote:
> >
> > On Wed, Dec 15, 2021 at 01:37:43PM -0500, Andrew Snyder wrote:
> > > That is probably true but I think on accident trying to replicate my
> > > original issue which was using the native function
> >
> > With the program:
> >
> > #include <stdio.h>
> > int main(int argc, char **argv)
> > {
> >         printf("%0*i\n", 2, argc);
> > }
> >
> > (written using argc so it can't be collapsed to a constant string at
> > compile time) I get output of "01\n" as expected. If you think there's
> > a bug in musl for this or related functionality, can you provide a
> > minimal C test case?
> >
> > > On Wed, Dec 15, 2021 at 1:09 PM Quentin Rameau <quinq@fifth.space>
> wrote:
> > >
> > > > Hi Andrew,
> > > >
> > > > > Sorry accidentally sent before attaching this
> > > > >
> > > > > ~# docker run -it --rm alpine /bin/ash
> > > > > / # /lib/libc.musl-x86_64.so.1
> > > > > musl libc (x86_64)
> > > > > Version 1.2.2
> > > > > Dynamic Program Loader
> > > > > Usage: /lib/libc.musl-x86_64.so.1 [options] [--] pathname [args]
> > > > > / # printf %0*i 2 1
> > > > > ash: %0*i: invalid format
> > > >
> > > > This looks like you found a bug in Busybox printf implementation.
> >
> > FWIW I suspect the problem is that Busybox is not recognizing the 0
> > character as a flag (which it is, in the printf grammar) and thinks
> > it's the leading character of a width, making the * specifier for
> > width invalid (since a width was already seen).
>
> yeah, since i was curious whether toybox had an issue too, i tested
> this (with bionic and glibc, but _not_ musl) and saw that coreutils
> and toybox both produce the correct output, but busybox fails with
> "invalid format" for glibc too.
>
> > Rich
>

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