October 2010 - Darwin-kernel

Re: alternatives to signals like try/catch
by Michael Smith 07 Oct '10

07 Oct '10

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Re: alternatives to signals like try/catch
by Daniel Walter 07 Oct '10

07 Oct '10

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Re: Semaphore questions?
by Michael Smith 07 Oct '10

07 Oct '10

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Re: Semaphore questions?
by Terry Lambert 06 Oct '10

06 Oct '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Oct 6, 2010, at 4:33 AM, sheetal phirke wrote: > Hello All, > > I am newbie in mac. i have query about following things with semaphore > > i am trying to use mach semaphore in IOKit. i have following questions :- > > 1: Do mach semaphore provide functions to get semaphore count? if not the why? No. You are supposed to know the value you set with semaphore_create(), and count it down. See: osfmk/kern/sync_sema.c <http://books.google.com/books?id=K8vUkpOXhN4C&pg=PA1219&lpg=PA1219&dq=amit+…> > 2: For mach semaphore one function available which is semaphore_signal_thread(), but for mac os x 10.6.2 i didn't found in semaphore.h? It's kernel private, which means is SPI for use in the OS implementation itself. It's not in the exported symbols list, and it's not available. In general, you don't know which thread(s) are waiting on the semaphore, so you don't know the thread parameter to pass to this function. It's basically an implementation detail for pthread condition variables in Libc, and should not be used by your code. > 3: I have try to go with POSIX semaphore, but it is not possible to implement in kernel. Correct. You can not use semaphores to communicate between the kernel and user space. Instead, you should use object wrappers such as IOCommandQueue or IOService. -- Terry > > Thanks, > Sheetal. _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Semaphore questions?
by sheetal phirke 06 Oct '10

06 Oct '10

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Re: alternatives to signals like try/catch
by Michael Smith 06 Oct '10

06 Oct '10

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Re: alternatives to signals like try/catch
by Daniel Walter 05 Oct '10

05 Oct '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Importance: Normal -setjmp/longjmp? Cheers, M _______________________________________________ _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… For shared objects such as ODBC drivers and browser plugins, it would be nice to handle signals without changing them in the main program. In Windows try/catch blocks handle these types of problems, but for Mac and Unix, there doesn't really seem to be a great alternative. The best I am seeing is to change all of the signals with sigaction one at a time every time a call passes into my shared object and change them all back with sigaction as this call returns. Are there any other alternatives? A third-party library should likely not be handling any signals- if this is about SIGPIPE, flip that off and check for EPIPE instead. I am writing the third-party library's and need these library's to handle signals. In particular I am looking to trap things like NULL pointer references and divide by zero errors, but SIGPIPE and other signals are important as well. We use crash dumps generated from these failures to improve our software quality. Additionally, our crashes are less damaging because they don't bring down larger applications. While I want to trap the problems that occur while executing my third party library code, I want my program to be generally well behaved and not screw around with the signals that occur while running the main program. Daniel This email sent to site_archiver(a)lists.apple.com

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Re: alternatives to signals like try/catch
by A.M. 05 Oct '10

05 Oct '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Oct 5, 2010, at 5:15 PM, Daniel Walter wrote: > For shared objects such as ODBC drivers and browser plugins, it would be nice to handle signals without changing them in the main program. In Windows try/catch blocks handle these types of problems, but for Mac and Unix, there doesn't really seem to be a great alternative. The best I am seeing is to change all of the signals with sigaction one at a time every time a call passes into my shared object and change them all back with sigaction as this call returns. Are there any other alternatives? -setjmp/longjmp? A third-party library should likely not be handling any signals- if this is about SIGPIPE, flip that off and check for EPIPE instead. Cheers, M _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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alternatives to signals like try/catch
by Daniel Walter 05 Oct '10

05 Oct '10

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Symbols missing in 10.6.4?
by Steve Modica 05 Oct '10

05 Oct '10

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Is anyone having trouble getting Shark to see symbol information in its outputs with 10.6.4? We have it loaded with the correct 10.6.4 kernel debugging kit mounted and it's still not seeing symbols (even those in the mach_kernel). Is anyone else having that problem? Steve -- Steve Modica CTO - Small Tree Communications www.small-tree.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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