Date: Tue, 15 Mar 2005 09:48:01 -0800 From: "Michael C. Shultz" <ringworm01@gmail.com> To: Daniel Eischen <deischen@freebsd.org>, freebsd-hackers@freebsd.org Subject: Re: threads question Message-ID: <200503150948.01624.ringworm01@gmail.com> In-Reply-To: <Pine.GSO.4.43.0503142350110.9058-100000@sea.ntplx.net> References: <Pine.GSO.4.43.0503142350110.9058-100000@sea.ntplx.net>
next in thread | previous in thread | raw e-mail | index | archive | help
On Monday 14 March 2005 08:57 pm, Daniel Eischen wrote: > On Mon, 14 Mar 2005, Michael C. Shultz wrote: > > Hi, I've just reached a point in a program I'm writing where I'd > > like to do threading. > > > > When I try to start a thread like this: > > > > pthread_create(&thread, &attr, MGPMrUpgrade, property ); > > ^^^^^^^^ &property > > You should compile with -Wall and get rid of any warnings. > > > where property is a structure of many variables it doesn't get > > passed to the function. If I do this: > > > > pthread_create(&thread, &attr, MGPMrUpgrade( &property ), NULL ); > > That looks like it will actuall call MGPMrUpgrade() and use its > return value as the function pointer. > > > It works, but just seems wrong. > > > > Can anyone point me to a source file, preferably in /usr/src > > somewhere that passes a structure to a function being run as a > > thread so I may study the proper way to do this? > > src/lib/libpthread/test/sem_d.c > src/lib/libpthread/test/mutex_d.c > src/lib/libpthread/test/sigwait_d.c > > I'd suggest getting Butenhof's "Programming with POSIX Threads" book. Daniel, sorry to bother you again but I ran into something that is either a bug or I am missing a vital piece of information somewhere. Here is the situation: this works perfectly because I moved MGPMrUpgrade into the same .c file so it would be a static function: structProperty* property; pthread_t threads[NTHREADS]; pthread_create( &threads[0], NULL, zzMGPMrUpgrade, property ); When I use MGPMrUpgrade from a shared library the function runs yet property isn't being passed! I remember from assembly days that there were some stack tricks to be done when making calls to a shared library in order to pass the parameters, I forget what they are (been ages since I did assembly programming) but anyways it seems like with gcc passing the args through the stack to a function in a shared library isn't being handled correctly. Am I missing something obvious? -Mike
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200503150948.01624.ringworm01>