public inbox for [email protected]  

help / color / mirror / Atom feed

From: Chao Li <[email protected]>
To: zhanghu <[email protected]>
Cc: [email protected]
Subject: Re: guc: make dereference style consistent in check_backtrace_functions
Date: Thu, 26 Feb 2026 17:21:13 +0800
Message-ID: <[email protected]> (raw)
In-Reply-To: <CAB5m2QssN6UO+ckr6ZCcV0A71mKUB6WdiTw1nHo43v4DTW1Dfg@mail.gmail.com>
References: <CAB5m2QssN6UO+ckr6ZCcV0A71mKUB6WdiTw1nHo43v4DTW1Dfg@mail.gmail.com>



> On Feb 26, 2026, at 15:03, zhanghu <[email protected]> wrote:
> 
> Hi,
> 
> In check_backtrace_functions(), most accesses to the input string follow the pattern (*newval)[i]. However, the empty-string check is currently written as:
> 
> if (*newval[0] == '\0')
> 
> While functionally correct due to how the compiler handles the address-of-address context here, this form is semantically misleading. It relies on implicit operator precedence rather than explicit intent.
> 
> The attached patch rewrites it as:
> 
> if ((*newval)[0] == '\0')
> 
> This change ensures semantic clarity and maintains a consistent dereferencing style throughout the function. No functional changes are introduced.
> 
> Regards,
> Zhang Hu
> <v1-0001-guc-make-dereference-style-consistent-in-check_ba.patch>

This is an interesting find.

[] has higher precedence than *, so:

 - (*newval)[i] means to get the first string, then get the char at position i
 - *newval[i] means to get the array element at position i, then get the first char

When i is 0, (*newval)[0] and *newval[0] happen to yield the same result, so this isn't a functional bug.

However, in the GUC context, newval is a point to a string rather than a two-dimension char array, *newval[i] is meaningless,  so +1 for fixing this to improve readability.

Best regards,
--
Chao Li (Evan)
HighGo Software Co., Ltd.
https://www.highgo.com/

view thread (3+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected]
  Subject: Re: guc: make dereference style consistent in check_backtrace_functions
  In-Reply-To: <[email protected]>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox