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* [Bug c++/107019] New: -Wunused-but-set-variable false positive for static variable in lambda with boost
@ 2022-09-23 15:03 mario at klebsch dot de
  2022-09-23 15:10 ` [Bug c++/107019] " mario at klebsch dot de
  2022-09-23 16:18 ` pinskia at gcc dot gnu.org
  0 siblings, 2 replies; 3+ messages in thread
From: mario at klebsch dot de @ 2022-09-23 15:03 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107019

            Bug ID: 107019
           Summary: -Wunused-but-set-variable false positive for static
                    variable in lambda with boost
           Product: gcc
           Version: 11.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: mario at klebsch dot de
  Target Milestone: ---

I get a palse positive from -Wunused-but-set-variable with this little sample:

#include <stdio.h>
#include <boost/asio.hpp>

int main(int argc, char *argv[])
{
    static const char *func = __FUNCTION__;
    boost::asio::io_service io_service;
    boost::asio::deadline_timer timer(io_service);
    timer.async_wait( [](auto) {
        printf("%s()\n", func);
    });
}

~/tmp $ g++  -Wall bug2.cpp   -c -I boost_1_80_0/
bug2.cpp: In function ‘int main(int, char**)’:
bug2.cpp:7:28: warning: variable ‘func’ set but not used
[-Wunused-but-set-variable]
    7 |         static const char *func = __FUNCTION__;
      |                            ^~~~
~/tmp $

If I do not call timer.async_wait() but some other function taking const
std::function<void(const boost::system::error_code&)>& as parameter, the usage
of func in the lambda is recognized correctly.

73, Mario

^ permalink raw reply	[flat|nested] 3+ messages in thread

* [Bug c++/107019] -Wunused-but-set-variable false positive for static variable in lambda with boost
  2022-09-23 15:03 [Bug c++/107019] New: -Wunused-but-set-variable false positive for static variable in lambda with boost mario at klebsch dot de
@ 2022-09-23 15:10 ` mario at klebsch dot de
  2022-09-23 16:18 ` pinskia at gcc dot gnu.org
  1 sibling, 0 replies; 3+ messages in thread
From: mario at klebsch dot de @ 2022-09-23 15:10 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107019

Mario Klebsch <mario at klebsch dot de> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |mario at klebsch dot de

--- Comment #1 from Mario Klebsch <mario at klebsch dot de> ---
Created attachment 53619
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=53619&action=edit
Sample demonstrating the bug

Needs boost-1.80.0
compile with g++  -Wall -c -I boost_1_80_0 bug2.cpp

> ~/tmp $ g++  -Wall -c -I boost_1_80_0 bug2.cpp
> bug2.cpp: In function ‘int main(int, char**)’:
> bug2.cpp:17:28: warning: variable ‘func’ set but not used [-Wunused-but-set-variable]
>    17 |         static const char *func = __FUNCTION__;
>       |                            ^~~~
> ~/tmp $

^ permalink raw reply	[flat|nested] 3+ messages in thread

* [Bug c++/107019] -Wunused-but-set-variable false positive for static variable in lambda with boost
  2022-09-23 15:03 [Bug c++/107019] New: -Wunused-but-set-variable false positive for static variable in lambda with boost mario at klebsch dot de
  2022-09-23 15:10 ` [Bug c++/107019] " mario at klebsch dot de
@ 2022-09-23 16:18 ` pinskia at gcc dot gnu.org
  1 sibling, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-09-23 16:18 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107019

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |DUPLICATE
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Dup of bug 88804.

*** This bug has been marked as a duplicate of bug 88804 ***

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2022-09-23 16:18 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2022-09-23 15:03 [Bug c++/107019] New: -Wunused-but-set-variable false positive for static variable in lambda with boost mario at klebsch dot de
2022-09-23 15:10 ` [Bug c++/107019] " mario at klebsch dot de
2022-09-23 16:18 ` pinskia at gcc dot gnu.org

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