possible snprintf() regression in 3.3.2

Corinna Vinschen corinna-cygwin@cygwin.com
Mon Nov 22 10:34:12 GMT 2021


On Nov 21 11:16, Tony Cook wrote:
> On Thu, Nov 18, 2021 at 09:08:40PM +0000, Sam Edge via Cygwin wrote:
> > I use newlib on embedded with threading libs that have predetermined
> > fixed thread stack sizes. While we tend to have more RAM than in former
> > times we also have multiple thread stacks. Use of alloca() or variable
> > length automatic arrays makes me wince especially in code I might not be
> > able to avoid calling which is often the case with XXXprintf() in
> > third-party libraries' debug output. I'd usually rather take the
> > performance hit from using heap instead of having to make all my stacks
> > bigger.
> 
> A simple option would be to use an small auto fixed buffer for most
> conversions, but use malloc() for %f formats for numbers greater in
> magnitude than some limit, though it would also need to be adjusted
> for the precision (ndigits here), since they take extra space.
> 
> This would avoid using the optional-to-implement VLA feature too.

Good idea.  I guess I create a simple fix doing just that.


Thanks,
Corinna


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