Re: Static Library Initialization (again?)

[Ramiro Polla <ramiro dot polla at gmail dot com>]

Hi,

On Thu, May 21, 2009 at 9:08 PM, Ramiro Polla<ramiro.polla@gmail.com> wrote:
> On Tue, Jun 17, 2008 at 8:27 PM, Brian Cole <coleb2@gmail.com> wrote:
>> It looks like I'm running into the same problem as others. I need to
>> distribute a static library with pthreads-win32 included without
>> requiring end-users of our library to call any pthreads-win32 specific
>> attach or detach code. Based on previous posts to the mailing list it
>> looks like the boost library has dealt with this before:
>> http://sourceware.org/ml/pthreads-win32/2008/msg00022.html
>>
>> I also found this bit of code inside the Google performance tools:
>> #ifdef _MSC_VER
>>
>> // This tells the linker to run these functions.
>> #pragma data_seg(push, old_seg)
>> #pragma data_seg(".CRT$XLB")
>> static void (NTAPI *p_thread_callback)(HINSTANCE h, DWORD dwReason, PVOID pv)
>> ? ?= on_tls_callback;
>> #pragma data_seg(".CRT$XTU")
>> static int (*p_process_term)(void) = on_process_term;
>> #pragma data_seg(pop, old_seg)
>>
>> #else ?// #ifdef _MSC_VER ?[probably msys/mingw]
>>
>> // We have to try the DllMain solution here, because we can't use the
>> // msvc-specific pragmas.
>> <snipped for brevity>
>>
>> #endif ?// #ifdef _MSC_VER
>>
>> Any reason pthreads-win32 can't use these same mechanisms to initialize itself?
>>
>> Why can't DllMain be used for this? MSDN seems to imply that DllMain
>> is called for static libraries
>> (http://msdn.microsoft.com/en-us/library/ms682583.aspx):
>> "The lpReserved parameter indicates whether the DLL is being loaded
>> statically or dynamically."
>>
>> I just looked through boost and found their implementation
>> (boost-trunk/libs/thread/src/win32/tss_pe.cpp). Any objection to me
>> creating a patch based on this code for pthreads-win32?
>
> I attached an ugly but working patch for this. I haven't tested
> building pthreads with MSVC but the initialization code worked on a
> standalone test app.
>
> I added a new make clean GC-autostatic to build the library.
>
> make clean GC-static tests pass. I also tested a bit with FFmpeg (but
> not extensively).
>
> I'm sure it can be dramatically improved (comments, documentation,
> stress test, etc), but as a start it's good enough.

For some reason I didn't get John E. Bossom's reply in my inbox, so
I'm quoting it here:

> Second, please beware that simply taking solutions from other open
> source components has the potential to taint the intellectual property
> rights of this open source component. open source doesn't mean free to
> copy... both Google and Boost are released under license and use of
> their code is subject to their respective license terms.
> pthreads-win32 had chosen to release under the LGPL in order to permit
> use by commercial software in addition to open source projects.
> However, commercial companies can come under fire for using open
> source components with questionable lineage. Some commercial companies
> will not touch an open source component if the maintainer does not
> maintain a list of all contributors and can prove the code base is not
> tainted.

I used boost as a reference:
https://svn.boost.org/trac/boost/browser/trunk/libs/thread/src/win32/tss_pe.cpp

The header reads:
// (C) Copyright Aaron W. LaFramboise, Roland Schwarz, Michael Glassford 2004.
// (C) Copyright 2007 Roland Schwarz
// (C) Copyright 2007 Anthony Williams
// (C) Copyright 2007 David Deakins
// Use, modification and distribution are subject to the
// Boost Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

The FSF affirms the boost license is GPL compatible, and from my
interpretation of the boost license, it is also LGPL compatible.

Whatever code is mine in that patch I license it as wtfpl <
http://sam.zoy.org/wtfpl/ >.

Ramiro Polla