[Bug c/28492] -Wmissing-format-attribute causes warning for vsnprintf()

[Bug c/28492] -Wmissing-format-attribute causes warning for vsnprintf()

[manu at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28492

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-04-17
                 CC|                            |manu at gcc dot gnu.org
     Ever Confirmed|0                           |1

--- Comment #3 from Manuel López-Ibáñez <manu at gcc dot gnu.org> 2012-04-17 22:17:01 UTC ---
OK, I see that the warning is misleading, because it points to the call of
vsnprintf instead of pointing to vsnprintf_one.

ttest.c: In function ‘vsnprintf_one’:
ttest.c:826:5: warning: function might be possible candidate for ‘gnu_printf’
format attribute [-Wmissing-format-attribute]
     vsnprintf(self, 2, "%c", arglist);
     ^

[Bug c/28492] -Wmissing-format-attribute points to vsnprintf() or related functions instead of the function that needs the attribute added

[manu at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=28492

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|2012-04-17 00:00:00         |2024-1-9

--- Comment #6 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
The option is called now -Wsuggest-attribute=format

See also https://gcc.gnu.org/pipermail/gcc/2024-January/243120.html for a
real-world case.

[Bug c/28492] -Wsuggest-attribute=format points to vsnprintf() or related functions instead of the function that needs the attribute added

[egallager at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=28492

Eric Gallager <egallager at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Summary|-Wmissing-format-attribute  |-Wsuggest-attribute=format
                   |points to vsnprintf() or    |points to vsnprintf() or
                   |related functions instead   |related functions instead
                   |of the function that needs  |of the function that needs
                   |the attribute added         |the attribute added

--- Comment #7 from Eric Gallager <egallager at gcc dot gnu.org> ---
(In reply to Manuel López-Ibáñez from comment #6)
> The option is called now -Wsuggest-attribute=format

OK, I fixed this part of the title now, too

[Bug c/28492] -Wmissing-format-attribute causes warning for vsnprintf()

[bernard dot van dot duijnen at oracle dot com]

------- Comment #2 from bernard dot van dot duijnen at oracle dot com  2010-04-04 15:08 -------
The message may be unclear, but is in itself correct.
Your function vsnprintf_one needs an annotation because
its first argument is a format string that can be checked itself
to be a valid format. As there are no arguments to compare to, the
first-to-check should be zero.


static void vsnprintf_one(char *self, va_list arglist)
   __attribute__ ((format (printf, 1, 0)));


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28492

[Bug c/28492] -Wmissing-format-attribute causes warning for vsnprintf()

[h dot b dot furuseth at usit dot uio dot no]

------- Comment #1 from h dot b dot furuseth at usit dot uio dot no  2007-01-13 18:40 -------
The warning is a bit misleading,
  "function might be possible candidate for 'printf' format attribute"
means the _calling_ function might be such a candidate, not the function
being called on the line it warns about.

The warning is still spurious in this case though, and gcc could tell that:
A function cannot be such a candidate if it has a prototype without variable
arguments.  Here is another example of such a spurious warning:

Hallvard


-- 

h dot b dot furuseth at usit dot uio dot no changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |h dot b dot furuseth at usit
                   |                            |dot uio dot no


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28492