On 7-Sep-2010, Ben Abbott wrote:
| On Sep 7, 2010, at 7:21 AM, Jarno Rajahalme wrote:
|
|> On Sep 7, 2010, at 3:30 , ext Ben Abbott wrote:
|>
|>> I understand the patch is needed for MacOS 10.6, but what of the early
versions?
|>>
|>> Thomas / anyone else, can you comment. Is the patch needed for ealier
versions of MacOS?
|>>
|>> Also does anyone understand how the ACX_PTHREAD macro can be modified to
detect the need for the -pthread option?
|>>
|>> For the details for why the patch is needed on MacOS 10.6, see the link
below.
|>>
|>>
https://www-old.cae.wisc.edu/pipermail/bug-octave/2010-January/010241.html
|>>
|>> Ben
|>
|> The change is 10.6 is in /usr/include/architecture/i386/math.h:
|>
|> /* lgamma and lgammaf are not thread-safe. The thread-safe variants
|> * lgamma_r and lgammaf_r are available on OS X 10.6 and later.
|> *
|> * To use the thread-safe variants, you must define the _REENTRANT
symbol.
|> */
|>
|> The -pthread compiler option causes gcc to define the required _REENTRANT
symbol. I have not tested whether lgamma_r and lgammaf_r depend on any specific
threading libraries, but if they do the -pthread option should cause them to be
linked in.
|>
|> OSX before 10.6 does not have the _r variants, but it seems to me that
having the -pthread option set should not break anything. Haven't tested it,
though.
|>
|> Jarno
|
| Ok! If the decision is not to detect (by a functional test) that -pthread is
needed, the case statement should be modified to reflect 10.6 only.
|
| The Darwin version numbers for the various MacOS versions are listed at the
link below.
|
| http://en.wikipedia.org/wiki/Darwin_(operating_system)
|
| Would the case statement function properly if it were written as ...
|
| case "${host_cpu}-${host_os}" in
| *solaris*)
|
| # On Solaris (at least, for some versions), libc contains stubbed
| # (non-functional) versions of the pthreads routines, so link-based
| # tests will erroneously succeed. (We need to link with
-pthreads/-mt/
| # -lpthread.) (The stubs are missing pthread_cleanup_push, or rather
| # a function called by this macro, so we could check for that, but
| # who knows whether they'll stub that too in a future libc.) So,
| # we'll just look for -pthreads and -lpthread first:
|
| acx_pthread_flags="-pthreads pthread -mt -pthread $acx_pthread_flags"
| ;;
|
| *-darwin10*)
|
| # On Darwin 10.x (MacOS 10.x), lgamma and lgammaf are not thread-safe.
| # The thread-safe variants lgamma_r and lgammaf_r are available on
| # OS X 10.6 and later. To use the thread-safe variants, you must
define the
| # _REENTRANT symbol. The -pthread compiler option causes gcc to define
| # the required _REENTRANT symbol.
|
| acx_pthread_flags="-pthread"
| ;;
| esac
|
| I'm not familiar with the tests done in these macros, but looking at
lo-specfun.cc:rc_lgamma, It doesn't look to me like creating a test for this is
straight forward (if I understand correctly a test would depend upon
HAVE_LGAMMA_R being defined true).
|
| Thoughts anyone? Is there an approach that can detect this problem, or should
the case statement be modified as done above?
Octave's acx_pthread.m4 file comes from the autoconf macro archive:
http://ac-archive.sourceforge.net/ac-archive/acx_pthread.html
Any changes to that file should be made upstream so everyone who uses
the file benefits. I'd prefer to avoid tracking our own modifications
to files from the autoconf macro archive, so please get the changes
made upstream first. Then once changes are in the autoconf macro
archive, we can copy the changes to the Octave sources.
Thanks,
jwe