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From: "msebor at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug c/97817] -Wformat-truncation=2 elicits invalid warning
Date: Fri, 13 Nov 2020 22:36:26 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D97817

Martin Sebor <msebor at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |msebor at gcc dot gnu.org
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|---                         |INVALID

--- Comment #3 from Martin Sebor <msebor at gcc dot gnu.org> ---
Level 2 of the warning is documented to warn also about calls to bounded
functions whose return value is used and that might result in truncation gi=
ven
an argument of sufficient length or magnitude.  The level is meant to help
write code with the least likelihood of truncation given unknown arguments.

In the test case, the output of the function will be truncated unless bufle=
n is
at least 16.  It will also be truncated if buflen is 16 and errnum is either
negative or bigger than 9.  The note printed after the warning indicates the
minimum size of output (i.e., 16) and the maximum (26) beyond which truncat=
ion
is impossible.=