Re: UBSAN errors in tinfo/read_entry.c's convert_32bits

[Thomas Dickey]

On Fri, Jan 06, 2023 at 09:29:55AM +0000, Sam James wrote:
> Hi,
> 
> When building ncurses 6.4 with UndefinedBehaviorSanitizer 
> (-fsanitize=undefined),
> I got the following when running `tput capname` (it happens during various 
> real world
> invocations of ncurses but this is the simplest);
> ```
> $ export UBSAN_OPTIONS=print_stacktrace=1:halt_on_error=0
> $ tput capname
> /var/tmp/portage/sys-libs/ncurses-6.4/work/ncurses-6.4/ncurses/tinfo/read_entry.c:92:24:
>  runtime error: left shift of 255 by 24 places cannot be represented in type 
> 'int'

I suppose masking before the shift might appease it (will investigate).

Knowing the version of gcc might help, in case that relates to the version
of UBSAN.

-- 
Thomas E. Dickey <dickey@invisible-island.net>
https://invisible-island.net

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