Re: Octave's m4/acx_pthread.m4 & OSX

[Jarno Rajahalme]

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