GNU bug report logs - #79240
Space inside C-strings

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Gisle Vanem <gvanem <at> yahoo.no>
To: bug-diffutils <at> gnu.org
Subject: Space inside C-strings
Date: Fri, 15 Aug 2025 10:27:06 +0200

I seem that "diff --ignore-space-change file1 file2"
ignores space-changes *inside* a C-string.

Like with file-1.c:
  char strFl[7] = "  ";
  char strTt[5] = "  ";
  char strGs[5] = "  ";

and file-2.c:
  char strFl[7] = " ";
  char strTt[5] = " ";
  char strGs[5] = " ";

"diff.exe -u3 -b file-1.c file-2.c" gives nothing.

I think this case should be OK for
"--ignore-all-space", not "-b" or "--ignore-space-change".
The manual does not mention spaces inside ""-strings AFAICS.

So how can I use diff to *not* ignore spaces inside C-stings,
but ignore trailing/leading spaces? A regular expression?

-- 
--gv

Message #8 received at 79240 <at> debbugs.gnu.org (full text, mbox):

From: Robert Webb <ro.webbdg <at> gmail.com>
To: 79240 <at> debbugs.gnu.org
Subject: Re: [bug-diffutils] bug#79240: Space inside C-strings
Date: Fri, 15 Aug 2025 16:48:20 -0700

On Fri, Aug 15, 2025 at 1:28 AM Gisle Vanem via bug-diffutils via All
diffutils discussion. <bug-diffutils <at> gnu.org> wrote:
> [...]
> So how can I use diff to *not* ignore spaces inside C-stings,
> but ignore trailing/leading spaces? A regular expression?

In bash:

  sedexpr='s/^  *//;s/  *$//'
  diff <(sed "$sedexpr" file-1.c) <(sed "$sedexpr" file-2.c)

-- 
Robert Webb

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