DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org D75153858D38
Message-ID: <eb49a355-95ad-b99f-d45e-19ff0ee94017@gmail.com>
Date: Wed, 12 Jul 2023 08:24:29 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101
 Thunderbird/102.13.0
Subject: Re: Linking a native msvc dll library to CYGWIN g++ compiler
To: cygwin@cygwin.com
References: <CAPxKPA4KfwWUa4pgEBuN=3ZDTYLP2QNGNo39nKhUtXFF_zGQ2A@mail.gmail.com>
In-Reply-To: <CAPxKPA4KfwWUa4pgEBuN=3ZDTYLP2QNGNo39nKhUtXFF_zGQ2A@mail.gmail.com>
From: =?utf-8?q?Csaba_R=C3=A1duly_via_Cygwin?= <cygwin@cygwin.com>
Reply-To: =?UTF-8?Q?Csaba_R=c3=a1duly?= <rcsaba@gmail.com>
Content-Type: text/plain; charset="utf-8"; Format="flowed"
Sender: "Cygwin" <cygwin-bounces+archive-cygwin=delorie.com@cygwin.com>
Content-Transfer-Encoding: 8bit

On 11/07/2023 08:47, Mümin A. via Cygwin wrote:
> Hi,
>
> I'm facing a problem while linking my native dll library into the g++
> compiler.
>
> There is a name mangling problem when calling a msvc function from g++
> compiler therefore linker gives an error undefined reference.
>
> Is there any method to directly link and call a function from native dll
> library from the cygwin compiler ?
>
>
>
> For example, I've a fooCls.h header file for a windows library,  I add link
> the fooCls.dll to g++ compiler then,
>
> fooNameSpace::fooConnectionCls instance;
> instance.FooTest();
>
> gives a linker error , undefined reference.

Hi,

GCC (and most compilers on Unix-like systems, even macOS) use the 
Itanium (IA64) ABI for C++ mangling:

https://itanium-cxx-abi.github.io/cxx-abi/abi.html#mangling

MSVC uses a different scheme, so the name of the symbol (as seen by the 
linker) expected by the object file compiled by GCC is different from 
the symbol supplied by the object file compiled with MSVC.

To link object files from GCC and MSVC together, you need to use C 
linkage (extern "C").

Csaba

-- 

Life is complex, with real and imaginary parts.


-- 
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple