March 2005 - Darwin-dev - lists.apple.com

Re: wchar_t and printf not working
by Alexey Proskuryakov 28 Mar '05

28 Mar '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com User-agent: Microsoft-Entourage/11.1.0.040913 On 28.03.2005 06:43, "Michael B Allen" <mba2000(a)ioplex.com> wrote: > For Darwin, or just about any other Unix based OS, you want to use the > non-wide character mode. Agreed. Just don't define XML_UNICODE and XML_UNICODE_WCHAR_T, and XML_Char becomes an UTF-8 encoded char. > Note that there are some minor gotchas to look out for when working > with UTF-8 though. For example you cannot necessarily iterate over each > character by simply examining each element in the array. Actually, that's not much of a drawback. You cannot index into UTF-16 strings, either - a single code point can be encoded as a surrogate pair in UTF-16. > Each character may occupy between 1 and 6 bytes [1]. More precisely, between 1 and 4: <http://www.unicode.org/faq/utf_bom.html#30>. >> Could it be that expat is assuming wchar_t is 2 bytes instead of the 4 >> bytes of darwin running on powerpc? > > I *think* Expat's wchar_t is hardcoded at 2 bytes (UTF-16LE) period. The byte order is certainly configurable (WORDS_BIGENDIAN in expat_config.h), and I *think* that expat happily stores UTF-16 in 4-byte wchars - after all, it would take them extra effort to break this. - WBR, Alexey Proskuryakov _______________________________________________ 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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sem_otime getting reset to 0
by Michael B Allen 28 Mar '05

28 Mar '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com After a semaphore is created the sem_otime member of semid_ds returned by an IPC_STAT will be initialized to 0. After the first semop call it is set to non-zero and AFAIK should never be reset to 0. However this is precisely what I'm seeing. Attached is a program [attachment removed and message resent due to list moderation - will send semc.c on demand directly] that performs a variety of semaphore operations. This command opens a semaphore with IPC_CREAT, IPC_EXCL, mode 777, 1 sem in the array, and initializes it's value to 10: $ ./semc /tmp/foo -o 1 1 777 1 10 CMD_OPEN: semid: 0 semnum: 0 path: /tmp/foo flags: oflags: O_CREAT|O_EXCL mode: 0777 numsems: 1 value: 10 393216 = cmd_open("/tmp/foo", 1, O_CREAT|O_EXCL, 0777, 10) We can query the value with: $ ./semc 393216 0 -g CMD_GETVAL: semid: 393216 semnum: 0 path: flags: oflags: mode: 0000 numsems: 0 value: 0 10 = cmd_getvalue(393216, 0, GETVAL) 10 is right. So far so good. But if we try to open the semaphore *without O_EXCL* there's a problem: $ ./semc /tmp/foo -o 1 0 777 1 10 CMD_OPEN: semid: 0 semnum: 0 path: /tmp/foo flags: oflags: O_CREAT mode: 0777 numsems: 1 value: 10 149: semid_get: Operation timed out Command failed The problem is that it is necessary to check sem_otime to make sure it is != 0 to avoid a race condition where a caller A creates a sem with semget but a second caller B swoops in, opens the sem and performs and operation (e.g. post, wait, getval, etc) before caller A has the opportunity to initialize the sem value with semop. The code to do this in the attached semc.c follows: 130 if ((semid = semget(key, nsems, 0)) != -1) { 131 struct semid_ds buf; 132 133/* This inner try-loop ensures that the semaphore is initialized before 134 * we return even if the semaphore has been created with semget but not 135 * yet initialized with semctl. See Stevens' UNPv2 p274. 136 */ 137 arg.buf = &buf; 138 for (max = MAX_TRIES; max; max--) { 139 if (semctl(semid, 0, IPC_STAT, arg) == -1) { 140 ERR(errno, "semctl"); 141 return -1; 142 } 143 if (buf.sem_otime != 0) { 144 return semid; 145 } 146 sleep(1); 147 } 148 149 ERR(errno = ETIMEDOUT, "semid_get"); 150 return -1; This hole in the API is described very well in Stevens' Unix Network Programming Volume 2 page 274. So the problem with Darwin is that creating a sem, exiting, and then opening the sem a second time appears to reset the sem_otime value. This code works as expected (sem_otime does not get reset to 0) on Linux 2.4, HP-UX, OSF1, and BSD. It's only Darwin that behaves differently. This is a major problem because there caller opening an existing semaphore will just hang waiting for the other non-existant program to initialize it. Pls advise, Mike -- IRC - where men are men, women are men, and the boys are FBI agents. _______________________________________________ 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: wchar_t and printf not working
by Michael B Allen 28 Mar '05

28 Mar '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On Sun, 27 Mar 2005 09:30:24 +1000 Warwick Hall <phosgate(a)unwired.com.au> wrote: > I have downloaded expat-1.95.8 (an XML cross platform C lib) and it has > the option of using UTF-16, which is passed around in wchar_t* > variables. I want to print these variables out to stdout, and i am not > having any luck. I think Expat's UTF-16 mode is largely for Windows and certain environments (are C++ strings always UTF-16?). For Darwin, or just about any other Unix based OS, you want to use the non-wide character mode. Just make sure you call setlocale(LC_CTYPE, ""). Then it's up to the environment of the user to ensure the locale encoding is UTF-8. I'd be willing to bet $1 Darwin is UTF-8 throughout by default. Note that there are some minor gotchas to look out for when working with UTF-8 though. For example you cannot necessarily iterate over each character by simply examining each element in the array. Each character may occupy between 1 and 6 bytes [1]. > Could it be that expat is assuming wchar_t is 2 bytes instead of the 4 > bytes of darwin running on powerpc? I *think* Expat's wchar_t is hardcoded at 2 bytes (UTF-16LE) period. Mike [1] http://www.cl.cam.ac.uk/~mgk25/unicode.html -- IRC - where men are men, women are men, and the boys are FBI agents. _______________________________________________ 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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AppleOnboardAudio-247.2.2 (darwin 7.8)
by Benjamin Herrenschmidt 27 Mar '05

27 Mar '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Hi ! Just a note: AppleOnboardAudio-247.2.2 (darwin 7.8) doesn't build. Though Darwin 7.8 isn't referenced from the main publicsource page, so I suppose it might just be "unsupported" release :) It seems like various codec type definitions are missing. Ben. _______________________________________________ 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: wchar_t and printf not working
by Alexey Proskuryakov 27 Mar '05

27 Mar '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com #include <stdio.h> #include <wchar.h> #include <locale.h> int main() { setlocale(LC_CTYPE, "en_US"); wchar_t buf[] = {1040, 1041, 1042, 0}; printf("Test: %ls\n", buf); // prints "Test: АБВ" wprintf(L"Test: %ls\n", buf); // same as above return 0; } - WBR, Alexey Proskuryakov _______________________________________________ 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 Sun, 27 Mar 2005 09:30:24 +1000 Warwick Hall <phosgate(a)unwired.com.au> wrote: I have downloaded expat-1.95.8 (an XML cross platform C lib) and it has the option of using UTF-16, which is passed around in wchar_t* variables. I want to print these variables out to stdout, and i am not having any luck. First of all, try running the following code. It should work, but you may need to re-configure Terminal for UTF-8 output. Wide chars in C have no encoding associated with them, and are virtually obsolete (they were introduced before Unicode emerged). Setlocale can make wprintf work in platform-dependent and not particularly reliable ways, though. Could it be that expat is assuming wchar_t is 2 bytes instead of the 4 bytes of darwin running on powerpc? The size of wchar doesn't seem relevant in this case. However, the en_US locale uses UTF-32 on Darwin, and I do not know if it's possible to specify UTF-16 (en_US.UTF-16 doesn't work). Most UTF-16 codes are equally good UTF-32 ones, so ignoring the difference may work for you while testing - but for production code this won't do, of course. This email sent to site_archiver(a)lists.apple.com

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wchar_t and printf not working
by Warwick Hall 26 Mar '05

26 Mar '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com All, This is my first post to darwin-dev and I hope this is on topic. I try: Regards, Warwick Hall _______________________________________________ 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 have downloaded expat-1.95.8 (an XML cross platform C lib) and it has the option of using UTF-16, which is passed around in wchar_t* variables. I want to print these variables out to stdout, and i am not having any luck. printf( "<format string>", element); where <format string> is "%s", or "%S", or "%ls". Nothing gets printed to screen. wprintf( L"<format string>", element); where <format string> is "%s", "%S", "%ls". Weird stuff gets printed to screen. Could it be that expat is assuming wchar_t is 2 bytes instead of the 4 bytes of darwin running on powerpc? This email sent to site_archiver(a)lists.apple.com

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Re: IOUSBDevice in IOUSBInterface comes opened?
by Fernando Urbina 26 Mar '05

26 Mar '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On Mar 26, 2005, at 10:02 AM, Ness Joumaa wrote: -- Fernando Urbina USB Technology Team Apple Computer, Inc. _______________________________________________ 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 have set the Provider Class in my plist that I want to get IOUSBInterface's. In my start function, I use the provider's (IOUSBInterface) GetDevice function to get the IOUSBDevice. Does GetDevice return an opened IOUSBDevice, or should I open it? Your question is better asked in the USB list @ http://lists.apple.com. That being said, GetDevice() does not do an implicit open. This email sent to site_archiver(a)lists.apple.com

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Re: gcc frontend?
by Marcel Weiher 26 Mar '05

26 Mar '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On 26 Mar 2005, at 19:49, Andrew Pinski wrote: On Mar 26, 2005, at 2:39 PM, Marcel Weiher wrote: ( options: --disable-libmudflap --enable-languages=c,objc ) - Is gcc-1765 really a good base? What would be a good/better base? - - Where could I get that? - Any other recommendations? Yes, I will do that. Thanks for the help! Cheers, Marcel _______________________________________________ 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… [trying to compile gcc from cvs] What is the error? There were initial errors trying to configure specific projects (getting the size of 'int' and such). Hardcoding those got me further, but there were further errors. Anyway: I just retried, but only enabling the C and Objective-C languages, and what do you know? It worked! :-) I disabled mudflap because I remembered that causing problems earlier, might not be absolutely necessary. Apple's gcc is not really a good place for working on a new front-end for GCC really. Also Apple's GCC depends on things being declared and really only supports the C family front-ends as you found out. Yep. Though apparently only doing C frontends also helps with the FSF GCC. I would use the mainline FSF gcc. There are only a few features which are in Apple's gcc which are not in the FSF's gcc. Most of them are C family based features which should not matter to a new front-end. This email sent to site_archiver(a)lists.apple.com

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Re: gcc frontend?
by Andrew Pinski 26 Mar '05

26 Mar '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com On Mar 26, 2005, at 2:39 PM, Marcel Weiher wrote: Hi folks, What is the error? - Is gcc-1765 really a good base? What would be a good/better base? - - Where could I get that? - Any other recommendations? -- Pinski _______________________________________________ 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 am trying to create a new gcc frontend, preferably using my OS X box and Apple's supplied gcc as the foundation, but having some difficulties. I first tried getting the "current" gcc from savannah, but that didn't want to compile at all with the gcc4.0 I have on my machine. The errors didn't look like I would be able to overcome them easily. Apple's gcc is not really a good place for working on a new front-end for GCC really. Also Apple's GCC depends on things being declared and really only supports the C family front-ends as you found out. I would use the mainline FSF gcc. There are only a few features which are in Apple's gcc which are not in the FSF's gcc. Most of them are C family based features which should not matter to a new front-end. This email sent to site_archiver(a)lists.apple.com

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gcc frontend?
by Marcel Weiher 26 Mar '05

26 Mar '05

site_archiver(a)lists.apple.com Delivered-To: darwin-dev(a)lists.apple.com Hi folks, - Is gcc-1765 really a good base? What would be a good/better base? - - Where could I get that? - Any other recommendations? Thanks, Marcel _______________________________________________ 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 am trying to create a new gcc frontend, preferably using my OS X box and Apple's supplied gcc as the foundation, but having some difficulties. I first tried getting the "current" gcc from savannah, but that didn't want to compile at all with the gcc4.0 I have on my machine. The errors didn't look like I would be able to overcome them easily. I then tried the gcc-1765 package. That compiled with a bit of tweaking, though the resulting compilers weren't usable. Leaving that "minor" issue for later, I pressed ahead. However, this gcc seems to be quite different from the baseline gcc, as far as I can tell. It took quite a bit of work to get the FLIM sample front-end ( http://people.csa.iisc.ernet.in/sreejith/frontends/flim/ ) to compile. Creating a custom front-end based on that, but including the C/Objective-C base required all sorts of symbols to be defined not mentioned anywhere in the documentation. I finally got that to compile/link after by providing stubs for the various required and am now in the process of providing actual code so it actually runs. However, before I go any further with this, I would like to ask wether I am moving in the right direction. This email sent to site_archiver(a)lists.apple.com

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