On Mon, Sep 09, 2002 at 12:02:02PM -0700, Brian Pane wrote: > Dave Hill wrote: > > >Hi all, > > While digging into that mysterious hang of Apache 2 on Tru64, > >I found that it seemed to be hanging under apr_poll in alloca() > >While I found that the problem seems to go away when not using a > >prerelease version of the OS, it did bring something to my attention. > > > >According to "Those Who Know", in a threaded environment on Tru64, we > >should be including alloca.h which causes the alloca() function to > >become a builtin (which They say is the one true way of avoiding > >threaded issues). This affects one (yes 1) file in the pool, > >srclib/apr/poll/unix/poll.c. Attached is a suggested change to include > >alloca.h if HAVE_ALLOCA is set. If my assumption is wrong that alloca > >is a universal include file (for machines that have alloca), then this > >could be restricted to Tru64, or maybe another conditional in > >configure :-p > > > > I like the idea of restricting the change to Tru64 for now, just > to eliminate the possibility of breaking something unexpected on > some other system this close to the 2.0.41 launch. Is there a > standard preprocessor macro that compilers on Tru64 define, so > that we can do something like "#if HAVE_ALLOCA && __TRU64__"?
Bison does something similar to: #if defined _AIX && !defined __GNUC__ #pragma alloca #endif #include <config.h> /* Make alloca work the best possible way. */ #ifdef __GNUC__ #define alloca __builtin_alloca #else /* not __GNUC__ */ #if HAVE_ALLOCA_H #include <alloca.h> #else /* not __GNUC__ or HAVE_ALLOCA_H */ #ifndef _AIX /* Already did AIX, up at the top. */ char *alloca (); #endif /* not _AIX */ #endif /* not HAVE_ALLOCA_H */ #endif /* not __GNUC__ */ This seems quite robust. -- albert chin ([EMAIL PROTECTED])
