Re: [Mingw-users] Dependency on libgcc_s_dw2-1.dll

[John B. <joh...@ho...>]

On  Fri, 18 Sep 2015 09:53:37 +0300, Eli Zaretskii wrote:
>
> [Please don't take this to private mail.]
>

Sorry about that. Normally when I reply, Outlook.com sends the response
to the list, but its behaviour seems to have changed. Now I have to 'Reply
All' and delete your private address.

>>
>> I don't understand. Why does gcc care who calls my C-language DLL?
>
> If the DLL you build will throw exceptions, not linking against shared
> libgcc will prevent those exceptions from being thrown and caught by
> other DLLs. GCC cannot know whether the applications or DLLs you are
> building expect that.
>

But I am not throwing exceptions, and if this behaviour is to prevent a
disaster that may or may not happen, why doesn't it do it all the time?

>> If my DLL (which neither catches nor throws C++ exceptions)
>
> (I don't think only C++ exceptions are affected. Windows supports
> exceptions in C code as well.)
>

It is true that when I build libThis and libThat I don't know whether they 
implement Windows Structured Exception Handling or not unless I inspect
the source. I consider it unlikely though.

>> is called by a C++ module, then let *that* module link to
>> libgcc_s_dw2.dll if it catches or throws exceptions.
>
> You need both the throwing and the catching code to link against the
> shared libgcc.
>

[snip]

> In any case, if you don't want the libgcc DLL dependency, and don't
> want to link against libgcc statically, what other options did you
> expect to exist?
>

I was hoping to avoid linking this (what I consider to be a) C++ DLL to my
C modules whether statically or dynamically, because I am not  (explicitly)
calling any functions in it. Of course, if the default action were to link statically,
I wouldn't have known that it was happening and I would have continued in
blissful ignorance.

Now that I know, I can follow your suggestion, but does it have any GPL
implications?

Regards,
John Brown.