Re: How to make a C++ -module?

Patrick,

Did you build the compiler yourself?  Basically Libtool is saying you only
have a static version of your runtime library, so if you built the compiler
yourself, add --enable-shared when you configure.  If not, I'll see if I
can get a NetBSD VM up and running so I can reproduce your problem, but at
first glance it appears to be your compiler.

Robert
On Jun 21, 2016 8:58 AM, "Bob Friesenhahn" <[email protected]>
wrote:

> On Tue, 21 Jun 2016, Patrick Welche wrote:
>
> I'm trying to create a C++ loadable module. I thought it would be as easy
>> as:
>>
>
> [ stuff removed ]
>
> This fails with:
>>
>> /bin/sh ./libtool  --tag=CXX   --mode=link g++  -g -O2 -module
>> -avoid-version  -o hellow.la -rpath /usr/local/lib hellow.lo
>>
>> *** Warning: linker path does not have real file for library -lgcc.
>> *** I have the capability to make that library automatically link in when
>> *** you link to this library.  But I can only do this if you have a
>> *** shared version of the library, which you do not appear to have
>> *** because I did check the linker path looking for a file starting
>> *** with libgcc and none of the candidates passed a file format test
>> *** using a regex pattern. Last file checked: /usr/lib/libgcc.a
>>
>> Presumably, this means that things aren't as simple as I thought.
>> What am I missing?
>>
>
> Nothing is easy when it comes to C++-based modules.  Risks are elevated if
> a C-based program uses C++-based modules due to unhandled C++ exceptions or
> C++ exceptions possibly not working.
>
> You are going to need a shared library for the (correct) C++ run-time as
> well as libgcc_s.so.  These need to somehow appear where libtool is
> searching for them.  They will also need to be available in a path where
> the system searches for shared libraries in order to load the module.
>
> # Dependencies to place before and after the objects being linked to
>> # create a shared library.
>> predep_objects="/usr/lib/crti.o /usr/lib/crtbeginS.o"
>> postdep_objects="/usr/lib/crtendS.o /usr/lib/crtn.o"
>> predeps=""
>> postdeps="-lstdc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc"
>>
>
> I am not sure what libgcc is used for.  It seems to only ever be delivered
> as a static library in the GCC installation tree.  Its appearance in the
> link line may be a bug (possibly a bug in GCC).
>
> Bob
> --
> Bob Friesenhahn
> [email protected], http://www.simplesystems.org/users/bfriesen/
> GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/
>
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>

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