Re: [PATCH v2] [gdb/remote] Reimplement escape_buffer

[Tom de Vries <tdevries@suse.de>]

On 3/23/26 3:12 PM, Tom Tromey wrote:
>>>>>> "Tom" == Tom de Vries <tdevries@suse.de> writes:
> 
> Tom> Reimplement function escape_buffer in gdb/remote.c, to print c_isprint chars
> Tom> like the actual chars, and others like octal escape sequences, getting us
> Tom> instead:
> 
> Tom> -  stb.putstrn (buf, n, '\\');
> 
> Supposedly putstrn does this quoting already.
> Why doesn't that work?  See ui_file::printchar.
> 

Aha, I read the header comment of putstr/putstrn and concluded from it 
that it wouldn't quote such chars.

Anyway, the way to make this work using putstrn is:
...
@@ -10515,6 +10515,7 @@ static std::string
  escape_buffer (const char *buf, int n)
  {
    string_file stb;
+  scoped_restore reset = make_scoped_restore (&sevenbit_strings, true);

    stb.putstrn (buf, n, '\\');
    return stb.release ();
...

> Tom> +      /* Append 3-wide leading zero octal \ooo.  */
> Tom> +      string_appendf (str, "\\%03hho", c);
> 
> I wonder if %hh actually works properly with the gdb format code.
> I don't recall ever seeing this before.
> 

The %hh is supported since c++11, so I suppose this is supported by the 
underlying vsprintf.

Thanks,
- Tom

> Tom