Re: shift-count-overflow possible issue on 64bit type

[Ponnuvel Palaniyappan <pponnuvel@gmail.com>]

The shift actually happens as int because the type of 1 is int, and the
result is then assigned to size_t. You can instead use a wider type:

size_t big = 1UL<<41;

On Sat, 23 Nov 2019, 13:56 Jonny Grant, <jg@jguk.org> wrote:

> I see on my 64bit Ubuntu PC that size_t is 8 bytes, that is 64bits,
> however I see a warning:
>
> $ g++-8 -Wall -Wextra -o size_t size_t.cpp
> size_t.cpp: In function ‘int main()’:
> size_t.cpp:11:21: warning: left shift count >= width of type
> [-Wshift-count-overflow]
>       size_t big = 1<<40;
>                       ^~
>
>
>
> Same on Godbolt trunk.
> Is this an issue?
>
> Regards, Jonny
>
> https://godbolt.org/z/xeefQ8
>
> #include <stdio.h>
> size_t big = 1<<41;
>
>
>
> Please keep my email on any replies
> Jonny
>