diff options
Diffstat (limited to 'ANNOUNCE')
| -rw-r--r-- | ANNOUNCE | 37 |
1 files changed, 29 insertions, 8 deletions
@@ -151,6 +151,8 @@ As defined in the new POSIX standard, and the Single Unix Spec version 3: pthread.h no longer includes windows.h
--------------------------------------
+[Not yet for G++]
+
This was done to prevent conflicts.
HANDLE, DWORD, and NULL are temporarily defined within pthread.h if
@@ -208,13 +210,19 @@ Known bugs in this snapshot Workaround [rpj - 2 Feb 2002]
-----------------------------
- The problem disappears when /Ob0 is used, i.e. /O2 /Ob0 works OK.
+ The problem disappears when /Ob0 is used, i.e. /O2 /Ob0 works OK,
+ but if you want to use inlining optimisation you can be much more
+ specific about where it's switched off and on by using a pragma.
So the inlining optimisation is interfering with the way that cleanup
- handlers are run. In order to confirm this, the following use of pragmas
- gets around the problem but I don't know how to make it transparent, in say,
- pthread.h where pthread_cleanup_push is a macro that expands (in the C++ case) to
- a local object instantiation with handlerFunc as the destructor (see pthread.h):
+ handlers are run. It appears to relate to auto-inlining of class methods
+ since this is the only auto inlining that is performed at /O1 optimisation
+ (functions with the "inline" qualifier are also inlined, but the problem
+ doesn't appear to involve any such functions in the library or testsuite).
+
+ In order to confirm the inlining culprit, the following use of pragmas
+ eliminate the problem but I don't know how to make it transparent, putting
+ it in, say, pthread.h where pthread_cleanup_push defined as a macro.
#pragma inline_depth(0)
pthread_cleanup_push(handlerFunc, (void *) &arg);
@@ -222,13 +230,26 @@ Known bugs in this snapshot /* ... */
pthread_cleanup_pop(0);
- #pragma inline_depth(8)
+ #pragma inline_depth()
+
+ Note the empty () value after the pop macro. This resets depth to the
+ default. Or you can specify a non-zero depth here.
The pragma is also needed (and now used) within the library itself wherever
cleanup handlers are used (condvar.c and rwlock.c).
- Use of these pragmas allows compiler optimisation /O2 to be used for
- both the library and applications.
+ Use of these pragmas allows compiler optimisations /O1 and /O2 to be
+ used for either or both the library and applications.
+
+ Experimenting further, I found that wrapping the actual cleanup handler
+ function with #pragma auto_inline(off|on) does NOT work.
+
+ MSVC6.0 doesn't appear to support the C99 standard's _Pragma directive,
+ however, later versions may. This form is embeddable inside #define
+ macros, which would be ideal because it would mean that it could be added
+ to the push/pop macro definitions in pthread.h and hidden from the
+ application programmer.
+
[/rpj]
Original problem description
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