Date: 02 Jul 1998 09:32:01 +0200 From: smoergrd@oslo.geco-prakla.slb.com (Dag-Erling Coidan Smørgrav) To: Joe Abley <jabley@clear.co.nz> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: pthreads Message-ID: <rx4g1gk4sjy.fsf@oslo.geco-prakla.slb.com> In-Reply-To: Joe Abley's message of Thu, 2 Jul 1998 08:09:39 %2B1200 (NZST) References: <Pine.BSF.3.96.980702080311.2083A-100000@buddha.clear.net.nz>
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Joe Abley <jabley@clear.co.nz> writes:
> 1. On Solaris, to compile a pthreaded program, I stick a
>
> #define _REENTRANT
> #include <pthread.h>
>
> at the top of the source files, and link with -lpthread.
Oh no you don't, unless you have an old Solaris or an old compiler. I
know the man pages tell you to do this, but the man pages are wrong...
You should just
#include <pthread.h>
#include <thread.h> /* if you want to use Solaris threads */
and compile with -mt. The compiler will define _REENTRANT itself, and
pass the correct arguments to ld.
A very good reason *not* to define _REENTRANT yourself is that you can
catch incorrect compilation:
#ifndef _REENTRANT
#error "This program needs to be compiled with the -mt option"
#endif
or even write your application in such a manner that it works without
threads, using #ifdef _REENTRANT / #else / #endif
For the record, I use the WorkShop Compilers 4.2 cc, dated 30 Oct
1996, on Solaris 2.5 and 2.6.
BTW, the Solaris thread implementation has a very nice feature which
POSIX threads lack: the ability to wait on all threads in one call,
like this:
while(thr_join(NULL, NULL, NULL) == 0)
/* nothing */ ;
This will block until all other threads terminate. Could there be some
loophole in the POSIX spec which would allow us to implement something
similar?
DES
--
Dag-Erling Smørgrav - smoergrd@oslo.geco-prakla.slb.com
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