Hi Toon, Caleb Epstein, Beman, Thomas Matelich,
Does anybody now any other flag that might influence this? Is it normal (never used readdir_r myself) that it is only defined in multi-threading-mode? From manpage of readdir_r:
"Users of readdir_r() should note that readdir_r() now conforms with the POSIX.1c Threads standard. The old prototype of readdir_r() is supported for compatibility with existing DCE applications only." _r denotes reentrant functions and -mt enables the following (for default -AA mode for aCC/Itanium): * -D_REENTRANT * -D_RW_MULTI_THREAD * -D_RWSTD_MULTI_THREAD * -D_POSIX_C_SOURCE=199506L * -D_HPUX_SOURCE * * -lpthread
Should we instruct bbv1 to compile the boost.filesystem always with the -mt flag on hpux ? Yes.
Yes that seems eminently reasonable (that readdir_r only be prototyped/available if -mt is supplied). Yes, since readdir_r is specifically for multithreaded code.
Well, there is code in libs/filesystem/src/operations_posix_windows.cpp that attempts to detect if it is being compiled with multi-threading enabled:
# if defined(_POSIX_THREAD_SAFE_FUNCTIONS) \ && defined(_SC_THREAD_SAFE_FUNCTIONS) \ && (_POSIX_THREAD_SAFE_FUNCTIONS+0 >= 0) Presumably aCC sets these macros incorrectly, or this code is not correct. Maybe the check should be for >0?
They are defined in <sys/unistd.h> (but the check will fail if the header file is not included).
Perhaps you can check what _POSIX_THREAD_SAFE_FUNCTIONS is defined to on aCC both with and without -mt? On Linux 2.4.21 + gcc 3.3.4, I get 200112 both with -pthread and without.
#include <pthread.h> #include <iostream> int main () { std::cout << _POSIX_THREAD_SAFE_FUNCTIONS << std::endl; }
It will fail in aCC if <unistd.h> is not included since -mt doesn't set these macros.
HP isn't like MS where you need uniform mt or not across all translation units if you want happiness, but I wouldn't think you'd want to enable mt settings behind the users' back.
I'm afraid its not, -mt needs to be defined consistently, otherwise there can be unexpected runtime problems.
Since somebody suggested that _REENTRANT is defined on HP when the '-mt' flag is used, what about only adding adding following to this #if
# if defined(_POSIX_THREAD_SAFE_FUNCTIONS) \ && defined(_SC_THREAD_SAFE_FUNCTIONS) \ && (_POSIX_THREAD_SAFE_FUNCTIONS+0 >= 0) || (defined(__HP_aCC) && defined(_REENTRANT)) I don't use boost build, but I thought the existing ifdef block seemed like it should work. I don't know much about HPUX on Itanium, but I went grepping on my HP 11i box, and found the _POSIX_THREAD_SAFE_FUNCTIONS define in /usr/include/sys/unistd.h. Right,
Then I remembered that to use the new posix friendly APIs on 11i, you need a -D_POSIX_C_SOURCE=199506L. I'd bet that if you added that to your build, things would work a lot more nicely. I think that define is only contra-indicated if you're still trying to use CMA threads (which is not a good idea). Yes, but setting -mt will take care of it. But I don't think its needed for the check we are doing here.
If you do end up needing a modification of the define block above, I'd recommend __hpux rather than __HP_aCC since this is a platform issue rather than a compiler issue. But, the problem is not with using g++ on HP-UX.
|| (defined(__HP_aCC) && defined(_REENTRANT))
I presume no change is needed if it is ensured (with a #ifdef guard?) that <unistd.h> is included before the check.
-Ganesh