Re: Extra import symbol in debug build

[i.nixman@autistici.org]

On 2023-02-16 20:08, Jonathan Wakely wrote:
> On Thu, 16 Feb 2023, 18:39 , <i.nixman@autistici.org> wrote:
> 
>> On 2023-02-16 15:29, Jonathan Wakely wrote:
>> > On Thu, 16 Feb 2023 at 15:25, i.nixman--- via Gcc-help
>> > <gcc-help@gcc.gnu.org> wrote:
>> >>
>> >> hello,
>> >>
>> >>
>> >> I can successfully build the same C++ code using GCC-8.3.1 for Debug
>> >> (-g
>> >> -O0) and Release (-g -O2) build.
>> >> I can successfully debug the Release-executable on a remote host, but
>> >> I
>> >> can't debug the Debug-executable on a remote host, because the
>> >> Debug-executable imports an extra symbol
>> >> _ZNKSt9basic_iosIcSt11char_traitsIcEEcvbEv from libstdc++ which
>> >> doesn't
>> >> exist.
>> >
>> > It should exist, it has been there since GCC
>> 
>> hmm...
>> 
>> I just checked the two binaries using this cmd:
>> 
>> > readelf -sW executable | grep
>> > _ZNKSt9basic_iosIcSt11char_traitsIcEEcvbEv
>> 
>> it shows nothing for release build, and shows this for debug build:
>> 
>> >     54: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND
>> > _ZNKSt9basic_iosIcSt11char_traitsIcEEcvbEv
>> > 199898: 0000000000000000     0 FUNC    GLOBAL DEFAULT  UND
>> > _ZNKSt9basic_iosIcSt11char_traitsIcEEcvbEv
>> 
> 
> 
> This only shows that the function is inlined in the optimized build, 
> and
> not in the debug build, so the debug one has an unresolved reference to 
> a
> symbol defined in the libstdc++ dynamic library. This is completely 
> normal.
> 

then I have two questions:

1. will the problem be solved by "pushing" a debug version of libstdc++ 
on the remote machine?

2. how can I define this symbol in the project code for debug build to 
avoid having to use the debug version of libstdc++?
something like this? :
namespace std {
    template basic_ios<char, char_traits<char> >::operator bool() const;
}




best!