October 2008 - Darwin-dev - lists.apple.com

Problems with aio_read
by Richard Schmitt 11 Oct '08

11 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com I'm trying to use aio_read in an application and am having problems with the completion notifications. When I use signals, I'll get a signal for the completion, but the siginfo structure does not have the si_value filled in. When I use notify functions, the aio_read call fails with invalid argument. Here's some sample code: my_action.sa_sigaction = my_handler ; my_action.sa_flags = SA_SIGINFO ; sigaction (SIGIO, &my_action, NULL) ; cb = malloc (sizeof (struct aiocb)) ; memset (cb, '\0', sizeof (struct aiocb)) ; cb->aio_fildes = open ("sigtest.c", O_NONBLOCK) ; cb->aio_buf = malloc (1001) ; cb->aio_nbytes = 1001 ; cb->aio_offset = 0 ; cb->aio_sigevent.sigev_value.sival_ptr = cb ; cb->aio_sigevent.sigev_signo = SIGIO ; cb->aio_sigevent.sigev_notify = SIGEV_SIGNAL ; ret = aio_read (cb) ; When the IO completes, I expect a SIGIO signal and the siginfo structure passed to my_handler will have the si_value set to the cb. The example handler is below: void my_handler (int sig, siginfo_t *siginfo, void* context) { struct aiocb *cb ; cb = siginfo->si_value.sival_ptr ; cb is always NULL. I'm running OSX 10.4.11 Thanks, Rich _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: New to Mac
by Steve Checkoway 10 Oct '08

10 Oct '08

site_archiver(a)lists.apple.com Delivered-To: Darwin-dev(a)lists.apple.com On Oct 9, 2008, at 10:20 PM, Steve wrote: g++ is indeed the c++ compiler front end. -- Steve Checkoway "Anyone who says that the solution is to educate the users hasn't ever met an actual user." -- Bruce Schneier _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com I see in /usr/bin there is also a cpp-4.0 and cpp-4.2, I'm assuming these are c++ compilers too? Not quite. cpp is the c preprocessor. You can always read the man page for most of the executables (among other things). For example, try man cpp in the terminal. I see in /usr/bin there is also the g++-4.0 and g++-4.2 also,,,,,,Duh! smime.p7s

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Re: New to Mac
by Steve 10 Oct '08

10 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Again thank you! Steve On Oct 9, 2008, at 10:08 PM, Kevin Van Vechten wrote: Hi Steve, - Kevin On Oct 9, 2008, at 9:56 PM, Steve wrote: /* energe.cpp */ /* Steve Young */ /* 10-08-08 */ #include <iostream> using namespace std; int main(){ cout<<"Where is that chicken gone to"; return 0; }//main Steve _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… Ok, that was dumb on my part. cc is a symbolic link to gcc 4.0 and I thought gcc was a c++ compiler. opps, my mistake, thx. I see in /usr/bin there is also a cpp-4.0 and cpp-4.2, I'm assuming these are c++ compilers too? I see in /usr/bin there is also the g++-4.0 and g++-4.2 also,,,,,,Duh! 'cc' is the C compiler; try using the 'c++' command to compile C++ code. I'm playing around trying to do some command line c++ coding, heres a stupid little program: And here's what I get from trying to compile it. What is going on here? steve-youngs-mac-pro:myc steve$ cc -o energy energy.cpp Undefined symbols: "___gxx_personality_v0", referenced from: ___gxx_personality_v0$non_lazy_ptr in ccVmTdM2.o "std::ios_base::Init::~Init()", referenced from: ___tcf_0 in ccVmTdM2.o "std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)", referenced from: _main in ccVmTdM2.o "std::ios_base::Init::Init()", referenced from: __static_initialization_and_destruction_0(int, int)in ccVmTdM2.o "std::cout", referenced from: __ZSt4cout$non_lazy_ptr in ccVmTdM2.o ld: symbol(s) not found collect2: ld returned 1 exit status steve-youngs-mac-pro:myc steve$ PS 1.)Let me know if there's a better list for these types of questions please? 2.)Are there any command line c++ tutorials for the Mac OS X? This email sent to site_archiver(a)lists.apple.com

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Re: New to Mac
by Kevin Van Vechten 10 Oct '08

10 Oct '08

site_archiver(a)lists.apple.com Delivered-To: Darwin-dev(a)lists.apple.com Hi Steve, 'cc' is the C compiler; try using the 'c++' command to compile C++ code. - Kevin On Oct 9, 2008, at 9:56 PM, Steve wrote: /* energe.cpp */ /* Steve Young */ /* 10-08-08 */ #include <iostream> using namespace std; int main(){ cout<<"Where is that chicken gone to"; return 0; }//main Steve _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… I'm playing around trying to do some command line c++ coding, heres a stupid little program: And here's what I get from trying to compile it. What is going on here? steve-youngs-mac-pro:myc steve$ cc -o energy energy.cpp Undefined symbols: "___gxx_personality_v0", referenced from: ___gxx_personality_v0$non_lazy_ptr in ccVmTdM2.o "std::ios_base::Init::~Init()", referenced from: ___tcf_0 in ccVmTdM2.o "std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)", referenced from: _main in ccVmTdM2.o "std::ios_base::Init::Init()", referenced from: __static_initialization_and_destruction_0(int, int)in ccVmTdM2.o "std::cout", referenced from: __ZSt4cout$non_lazy_ptr in ccVmTdM2.o ld: symbol(s) not found collect2: ld returned 1 exit status steve-youngs-mac-pro:myc steve$ PS 1.)Let me know if there's a better list for these types of questions please? 2.)Are there any command line c++ tutorials for the Mac OS X? This email sent to site_archiver(a)lists.apple.com

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New to Mac
by Steve 10 Oct '08

10 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: Is it guaranteed safe to pass NULL to free()?
by Terry Lambert 09 Oct '08

09 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Yes, by both. <http://www.opengroup.org/onlinepubs/009695399/functions/free.html> -- Terry _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… On Oct 8, 2008, at 5:13 PM, Sean McBride wrote: My understanding is that one can safely pass NULL to free(). I've seen this stated in man pages on various unices. However, I notice that Mac OS X 10.5's man page for free makes no comment about passing NULL. Is it guaranteed safe by posix or the C standard, or not? Also The ANSI/ISO C specification, section 7.20.3.2, The free function, paragraph 2. This is to accomodate historical implementations of the free() functions which, when called with a NULL argument, manually triggered garbage collection on freed but uncollected pages, for example in power-of-2 allocators. This email sent to site_archiver(a)lists.apple.com

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Re: Is it guaranteed safe to pass NULL to free()?
by Patrick Rutkowski 09 Oct '08

09 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:cc:message-id:from:to :in-reply-to:content-type:mime-version:subject:date:references :x-mailer; bh=pbiiEtcjREzwocz1+kZkl7RNh2BxOCmmEyYT3Uy+AlE=; b=gnH0zRXy1ZRnU12OXceThM9ipm+CH/X2DxH7egCSs24PJ83z6LEkUWKdTOTsC710BA dUtpLwNK/WB4r1Hnakd4RJz5PkYcH3XZhG9pD9TbkyAo2Egw64ONJfMbkJ07jQvjQW47 WrbkSPP9Rpd6xf3HGK4GEZg+sRluxsu9ca2CE= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=cc:message-id:from:to:in-reply-to:content-type:mime-version:subject :date:references:x-mailer; b=GRo+afxslUhFXAheJ5oKQpm7zIzfD4QM6wQFpJlrbKVTr5sai8zVXnA6giKslZSKWv M+RRksvQuOWnitx3SXcIerVrbTx1nWLp0mwckSmSyjEgfPxGpuhTwnP0nx9tAd1NaeRn D+auZ0K7yQ4XgmsH39v9ughCEzKjnFY0yLL+E= _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: Is it guaranteed safe to pass NULL to free()?
by Brian Mastenbrook 09 Oct '08

09 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On Oct 8, 2008, at 7:13 PM, Sean McBride wrote: Yes. It is guaranteed safe by the C standard. -- Brian Mastenbrook brian(a)mastenbrook.net http://brian.mastenbrook.net/ _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… My understanding is that one can safely pass NULL to free(). I've seen this stated in man pages on various unices. However, I notice that Mac OS X 10.5's man page for free makes no comment about passing NULL. Is it guaranteed safe by posix or the C standard, or not? This email sent to site_archiver(a)lists.apple.com

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Is it guaranteed safe to pass NULL to free()?
by Sean McBride 09 Oct '08

09 Oct '08

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Organization: Rogue Research Hi all, My understanding is that one can safely pass NULL to free(). I've seen this stated in man pages on various unices. However, I notice that Mac OS X 10.5's man page for free makes no comment about passing NULL. Is it guaranteed safe by posix or the C standard, or not? Cheers, -- ____________________________________________________________ Sean McBride, B. Eng sean(a)rogue-research.com Rogue Research www.rogue-research.com Mac Software Developer Montréal, Québec, Canada _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… This email sent to site_archiver(a)lists.apple.com

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Re: daemon-child dies on user lougout
by Terry Lambert 08 Oct '08

08 Oct '08

site_archiver(a)lists.apple.com Delivered-To: Darwin-dev(a)lists.apple.com Hi, - daemon is running as root - daemon fork()s a child, that setuid()s to some user - child exec()s some worker program - worker connects on a socket to the daemon, using ICE (www.zeroc.com) - if the worker runs as current GUI user, and that user logs out, the worker dies/crashes. - if the worker runs as any other system user, all works fine. -- Terry _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-dev mailing list (Darwin-dev(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-dev/site_archiver%40lists.app… On Oct 7, 2008, at 5:21 AM, Mario Emmenlauer wrote: I'm picking up on a thread called 'launchd daemon, spawning children?'. Terry Lambert wrote: On Oct 1, 2008, at 3:40 AM, Mario Emmenlauer wrote: One last question: If "worker_user" is the current GUI-user, all his applications get killed on logout. Is there a way around this (or would using 'login' also solve this issue?) The logout operation for non-GUI applications sends either a SIGHUP (the correct signal), or a SIGTERM (not the correct signal). You can ignore or catch these signals with a signal handler, although if you ignore SIGTERM, you will delay shutdowns. In general, daemons running as that user are not kiplled unless they are in the process group, or their parent is the per-session launchd. Otherwise, you would not be able to ssh into a machine and log out of a GUI and not have it kill your ssh (which it doesn't do). Seems only logical. But I have an odd behavior there, my application dies on user-logout. Here is the scenario: ReportCrash saves a report similar to the one attached. The only thing my child and server are doing are the network connection, and some disk usage. When I use a dummy worker that does nothing (sleeps), it doesn't die (and gets no SIGTERM or SIGHUP sent, as Terry already predicted). So I can only imagine that the logout kills the ICE socket connection for that user? Does that make any sense to anyone? The most likely scenario is that the process running in the background sets up some UI component or another as a result of the framework(s) it is using under the covers, and as a result, ends up becoming dependent on the WindowServer; when the user logs out, that goes away and the process ends up shutting down for lack of the dependency. Without knowing exactly all of the communications channel resources (workloops, sockets, mach ports, ptys, pipes, named pipes, etc.) being used by the process, and what's on the other end of those channel resources, it's rather hard to diagnose something like this remotely. Your best bet would be to start small; I imagine a very simple program that did a "while(1) sleep(1000);" would not have this problem. Add things back in until it starts exhibiting the behaviour, and you'll have found your culprit. This email sent to site_archiver(a)lists.apple.com

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