[Qt-interest] Question about license requirement on redistributing libgcc shared library

[Christoph Würstle]

Hi,

I came to the same result. But I'm also not familiar with this exception.
What I found out, is that many commercial programs link (dynamically)
against libgcc (at least on Linux), such as FlashPlayer, Acrobat Reader,
Skype.
So your understanding should be right, because I don't think they were
able to "buy" the code (from Gcc).

It would be very nice, if someone who knows it confirms it. Thanks.

Chris

> Hello,
>
> Please help me to understand about the license requirement on 
> redistributing libgcc shared library, to be specific, the dll file 
> "libgcc_s_dw2-1.dll".  I am using Qt SDK 4.6.1 for Windows(MinGW) 
> under the LGPL, and that dll file is placed in the folders 
> "2010.01\mingw\bin" and "2010.01\qt\bin" by default.
> I am going to distribute a package that consists of the files:
>   - Qt application(.exe) file developing, under a proprietary license
>   - "Qt*.dll" files, under the LGPL v2.1
>   - "mingwm10.dll" of MinGW runtime, public domain
>   - "libgcc_s_dw2-1.dll", ...
>
> I understand that "GCC Runtime Library Exception Version 3.1" is 
> applied as license of libgcc, based on the following sentence 
> described in the source files of libgcc:
>   "Under Section 7 of GPL version 3, you are granted additional
>    permissions described in the GCC Runtime Library Exception, version
>    3.1, as published by the Free Software Foundation."
>
> Looking into "GCC Runtime Library Exception v3.1" and "rationale 
> document and FAQ" (see http://www.gnu.org/licenses/gcc-exception.html), 
> it seems for me that redistributing "libgcc_s_dw2-1.dll" is permitted 
> and no obligation is required if the following condition is met:
>   - All files linked with libgcc are "Independent Module" for libgcc.
>     and 
>   - All "Target Code" was generated by "Eligible Compilation Processes".
>
> So my questions in brief are:
>   - In my understanding, redistributing "libgcc_s_dw2-1.dll" is 
>     granted without any obligation such as providing its source code 
>     and copyright/legal notice, if the above condition is met.
>     Is this correct?
>   - All "Qt*.dll" files in Qt SDK are "Independent Module" for libgcc?
>   (Please refer to the above link for definition of term.)
>
> Any help will be appreciated, since I am not very familiar with GPL 
> licenses.
>
> Regards,
> Koji Ishihara