Re: [PATCH] trace2: refactor to avoid gcc warning under -O3

[Jeff King <peff@peff.net>]

On Wed, May 05, 2021 at 06:47:29PM +0900, Junio C Hamano wrote:

> The patch makes sense to me, modulo that the way the variable
> "saved_errno" introduced by this patch is used and the way a
> variable with that name is typically used in our codebase are at
> odds.  I.e. we typically call a variable "saved_errno" when it is
> used in this pattern:
> 
>     if (a_syscall_whose_error_condition_we_care_about()) {
> 	int saved_errno = errno;
> 	perform_some_cleanup_operation_that_might_clobber_errno();
> 	return error_errno(..., saved_errno);
> 	/*
> 	 * or
> 	 * errno = saved_errno;
> 	 * return -1;
> 	 * and let the caller handle 'errno'
> 	 */
>     }
> 
> But since I do not think of a better name for this new variable that
> is not exactly used like so, let's queue it as-is.

I'd probably have just called it "err", but I think it is fine either
way. :)

The patch also looks good to me. I used to compile with -O3 occasionally
to fix warnings, but given the date on this commit, it seems I have not
done so in quite a while. (It reproduces on gcc 10 for me, which is not
surprising).

-Peff