On Sun, Jul 09, 2023 at 02:42:55PM +0800, Linke Li wrote:
> From: Linke Li <lilinke99@xxxxxxxxx>
>
> Fix undefined behavior in the code by properly handling the left shift operaion.
> Instead of left-shifting a negative value, explicitly cast -1 to an unsigned int
> before the shift. This ensures well defined behavior and resolves any potential
> issues.
This certainly fixes the problem, but wouldn't it be easier to get the
compiler to do the work for us?
#include <stdio.h>
int f(unsigned char *p)
{
return (signed char)p[0];
}
int main(void)
{
unsigned char x = 0xa5;
printf("%d\n", f(&x));
return 0;
}
prints -91.
