Le 2015-10-06 20:43, wm4 a écrit :
On Tue, 6 Oct 2015 12:41:13 +0200
Hendrik Leppkes <[email protected]> wrote:
The emulation uses native InitOnce* APIs on Windows Vista+, and a
lock-free/allocation-free approach using atomics and spinning for
Windows XP.
---
This is in preparation to use pthread_once for global static init
functions,
and eventually removing the global lock in avcodec_open2
compat/w32pthreads.h | 68
++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 68 insertions(+)
Somewhat related to this patch, we were discussing ways to deal with
w32thread_init().
Personally, I think we should not have to litter the code with
w32thread_init() calls. Nor should the user somehow have to make
sure that this function is somehow called implicitly, when calling
API functions which use threads.
There are a few ways to handle this:
1. Don't handle it, but put it e.g. in avcodec_register_all(), and
hope
the user calls it before calling other APIs which might require
it.
2. Call it from DllMain() only. This breaks static linking, or
requires
special care if an application uses a statically linked libav.
3. Make w32thread_init() thread-safe, and call it from all
entrypoints
that need it, like pthread_cond_init() and pthread_once().
4. Remove the *run-time* Windows Vista+ support. People get to choose
the better Vista+ or the crappy NT5 CV implementation at build time.
5. Drop support for Windows 2003 and older completely. Even MSDN
started dropping documentation for it.
Either way, the function is no longer necessary at all.
--
Rémi Denis-Courmont
http://www.remlab.net/
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