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Static link (MSVC), alteration proposal


 Hello.
 I show (as short as I can) a small note about statically
linking to the Pthreads-Win32 library.

 My deprecation: why using _DLL macro to determine whether
to link statically or dynamically? As you know, _DLL is
used by the Microsoft headers; when defined, it links your
app/lib/dll with an import library, which by itself points
to the dynamically linked libraries, containing
implementation of the C-Runtime Library on Win32. When _DLL
not defined, C-Runtime is linked statically into your
app/lib/dll. So, why the type of the linkage with the
C-Runtime is bound to the type of linkage with
Pthreads-Win32?

 In order to link my dll with Pthreads-Win32 statically, I
had to do some minor changes:

1. Code in <pthread.h> which I altered:

#ifdef _DLL
# ifdef PTW32_BUILD
#  define PTW32_DLLPORT __declspec (dllexport)
# else
#  define PTW32_DLLPORT __declspec (dllimport)
# endif
#endif

with:

#ifdef PTW32_DLL
#  ifdef PTW32_BUILD
#    define PTW32_DLLPORT __declspec (dllexport)
#  else
#    define PTW32_DLLPORT __declspec (dllimport)
#  endif
#else
#define PTW32_DLLPORT
#endif

You surely realize what I do: First, I use a separate macro
to determine whether to link statically or dynamically to
Pthreads-Win32. Second, if you not explicitly define
PTW32_DLLPORT as an empty macro, MSVC compiler expands it
to __declspec(dllimport), no matter of the fact, that the
preprocessor does not actually enter in the #ifdef
PTW32_DLL block!! It's so funny. Of course, I did not
wasted my time to check some strange implications which
could be made by the MSVC compiler, since it always knows
better than you what you actually want. :)

2. In <semaphore.h> and <sched.h> preprocessor code was
similar, with the difference that there were no #ifdef
_DLL. There I changed the code exactly as in <pthread.h>

3. In <pthread.c> I altered the following code:

#include <dll.c>

with:

#ifdef PTW32_DLL
#include <dll.c>
#endif

---

 The result of all this is: when you do not define PTW32_DLL
in your build, you will be sure that Pthread-Win32
function's declarations will not contain
__declspec(dllexport) / __declspec(dllimport). Also, when
you build your own DLL, you assure that no conflict will
occur with the Pthread-Win32's DllMain().

 Sorry for the bad English, it's not my native language.

 Of course, one human does not need to be a genius to note
such things, nor will I pretend to be very smart for
writing this note. :) I just hope it to be useful.

---------------------
| Dimitar Panayotov |
| develop@mail.bg   |
| +359886420488     |
---------------------

-----------------------------

"Константин"  -  Джон Константин (Киану Рийвс) вече е бил в ада.
Той има дарбата да разпознава демоните, приели човешки облик.
http://www.mail.bg/info/?action=1200&title=%CA%EE%ED%F1%F2%E0%ED%F2%E8%ED%20%282005%29&date


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