Re: Mixing Obj-C and C methods
My common way of handling this would be NSNotificationCenter. It is a singleton so I am always sure that it is there, and I can wrap all parameters into the userInfo dictionary. Sent from my iPhone On 2013年7月30日, at 21:19, KappA rejek...@gmail.com wrote: I sometimes just access my objc-objects from a C thread-proc via the AppDelegate (providing there's a trail to the object I need, which there usually is)... If the callback void pointer parameter isn't being used for something else, you can simply cast the object in there... or if you need multiple parameters you can create a struct that stores what you need and pass that. Not sure if this helps but figured I'd mention it. AppDelegate *d = [[UIApplication sharedApplication] delegate]; On Tue, Jul 30, 2013 at 8:53 AM, lowell lowe...@me.com wrote: The first two parameters to the function have to be an id and a SEL ... typedef id (*IMP)(id, SEL, ...); ... (this is where we get self and _cmd, by the way) followed by the rest of the method params, if any. lowell On Jul 30, 2013, at 12:59 AM, Vincent Habchi vi...@macports.org wrote: Hi everybody, I have a very simple question: if I embed a C-function (more precisely, a callback from an external C-library) in an Obj-C object, can I expect this function to behave like a regular method? I.e. can it freely access ‘self’ and other attributes? Thanks a lot! Vincent ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/lowellv%40me.com This email sent to lowe...@me.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/rejekted%40gmail.com This email sent to rejek...@gmail.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/xcvista%40me.com This email sent to xcvi...@me.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Synchronous Serial Port Protocol messaging With NSOperationQueue/GCD
hi everyone, I'm writing a mac osx app that needs to talk to a serial device. There's a well known protocol to adhere to (implemented in the device firmware) and is a kind of a half-duplex synchronous protocol where if i send a message to the device from my app i have to wait till i get a response from the device, inspect it and then i'm allowed to send another message. This has to go for several messages i need to send to the device. Given this synchronous nature, i'm trying to keep the UI free so i'm doing all the messaging stuff on background threads. My choice is to use NSOperation and NSOperationQueue, where the queue is configured with maxConcurrentOperations set to 1 in order to have a strict serial behavior (this is due to the constraints given by the implemented protocol). How can i make an NSOperation subclass waiting for a signal given by the serial port delegate to make it fire isFinished KVO to the queue and make that queue consequently execute the next NSOperation? Does this approach make sense to you? I'm open to any suggestions of course. Thank you! Vanni ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
How to convert an NSString to
Hi all, I need to convert a normal: NSString * string = @Ich möchte am Wettbewerb teilnehmen to something like this: NSString * string = @Ich%20möchte%20am%20Wettbewerb%20teilnehmen I don´t want to do this manually. Any clues how to do it with Objective-C ? Greetings from Switzerland, Ronald Hofmann --- ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Mixing Obj-C and C methods
On 30 Jul 2013, at 15:44, Maxthon Chan xcvi...@me.com wrote:
My common way of handling this would be NSNotificationCenter. It is a
singleton so I am always sure that it is there, and I can wrap all parameters
into the userInfo dictionary.
NSNotificationCenter is not a singleton:
$ cat test.m
#import Foundation/Foundation.h
int main (int argc, char **argv)
{
@autoreleasepool
{
NSNotificationCenter *a = [[[NSNotificationCenter alloc] init]
autorelease];
NSNotificationCenter *b = [[[NSNotificationCenter alloc] init]
autorelease];
NSLog(@%p, %p, a, b);
}
$ clang -framework Foundation test.m
$ ./a.out
2013-08-07 09:13:25.508 a.out[6155:507] 0x7fcb1040a090, 0x7fcb1040a190
It just happens to have one instance (defaultNotificationCenter) which is
common to want to use in lots of locations in your program.
You can not “be sure that [a singleton] is there” any more or less than any
other class in your program.
For reference though, both designs for effectively making all objects in your
program global objects are pretty horrible for exactly that reason – making
everything effectively a global is just terrible design.
Tom Davie
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Re: How to convert an NSString to
Hi, Have you tried: [@Ich möchte am Wettbewerb teilnehmen stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; Granted, this will also replace the ö with its percent escaped variant, which you probably want anyway. Best, Igor Elland On Aug 6, 2013, at 1:45 PM, Ronald Hofmann pro...@jumbosoft.de wrote: Hi all, I need to convert a normal: NSString * string = @Ich möchte am Wettbewerb teilnehmen to something like this: NSString * string = @Ich%20möchte%20am%20Wettbewerb%20teilnehmen I don´t want to do this manually. Any clues how to do it with Objective-C ? Greetings from Switzerland, Ronald Hofmann --- ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/igor.elland%40me.com This email sent to igor.ell...@me.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Synchronous Serial Port Protocol messaging With NSOperationQueue/GCD
On 1 Aug 2013, at 12:03, Vanni Parronchi vanniparron...@gmail.com wrote: hi everyone, I'm writing a mac osx app that needs to talk to a serial device. There's a well known protocol to adhere to (implemented in the device firmware) and is a kind of a half-duplex synchronous protocol where if i send a message to the device from my app i have to wait till i get a response from the device, inspect it and then i'm allowed to send another message. This has to go for several messages i need to send to the device. Given this synchronous nature, i'm trying to keep the UI free so i'm doing all the messaging stuff on background threads. My choice is to use NSOperation and NSOperationQueue, where the queue is configured with maxConcurrentOperations set to 1 in order to have a strict serial behavior (this is due to the constraints given by the implemented protocol). How can i make an NSOperation subclass waiting for a signal given by the serial port delegate to make it fire isFinished KVO to the queue and make that queue consequently execute the next NSOperation? Does this approach make sense to you? My suggestion would instead be to make an NSOperation subclass for sending a message to the device. That subclass should require you to specify to which device you are talking. Each device object should carry around a dispatch_semaphore. When a message is sent, the semaphore should be checked and set to stop any other operations proceeding until the semaphore is unset. When the device responds, the semaphore should be unset. You can then make your operation queue a concurrent queue, rather than a serial one, so that you can send messages to more than one device at the same time, while still maintaining your one-thing-at-a-time per device rule. Tom Davie ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: How to convert an NSString to
Or if you just want to convert the spaces: string = [@Ich möchte am Wettbewerb teilnehmen stringByReplacingOccurrencesOfString:@ withString:@%20]; On Aug 7, 2013, at 9:19 AM, Igor Elland igor.ell...@me.com wrote: Hi, Have you tried: [@Ich möchte am Wettbewerb teilnehmen stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; Granted, this will also replace the ö with its percent escaped variant, which you probably want anyway. Best, Igor Elland On Aug 6, 2013, at 1:45 PM, Ronald Hofmann pro...@jumbosoft.de wrote: Hi all, I need to convert a normal: NSString * string = @Ich möchte am Wettbewerb teilnehmen to something like this: NSString * string = @Ich%20möchte%20am%20Wettbewerb%20teilnehmen I don´t want to do this manually. Any clues how to do it with Objective-C ? Greetings from Switzerland, Ronald Hofmann --- ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/igor.elland%40me.com This email sent to igor.ell...@me.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/tamas.lov.nagy%40gmail.com This email sent to tamas.lov.n...@gmail.com ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: How to convert an NSString to
Or if you just want to convert the spaces: string = [@Ich möchte am Wettbewerb teilnehmen stringByReplacingOccurrencesOfString:@ withString:@%20”]; Please avoid using that, if you really need **only** white space to be replaced, you want to use [@Ich möchte am Wettbewerb teilnehmen stringByReplacingCharactersInSet:[NSCharacterSet whitespaceCharacterSet] withString:@%20”] instead, as there are different UTF-8 characters for different kinds of whitespace. ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: How to convert an NSString to
On 7 Aug 2013, at 09:24, Igor Elland igor.ell...@me.com wrote: Or if you just want to convert the spaces: string = [@Ich möchte am Wettbewerb teilnehmen stringByReplacingOccurrencesOfString:@ withString:@%20”]; Please avoid using that, if you really need **only** white space to be replaced, you want to use [@Ich möchte am Wettbewerb teilnehmen stringByReplacingCharactersInSet:[NSCharacterSet whitespaceCharacterSet] withString:@%20”] instead, as there are different UTF-8 characters for different kinds of whitespace. This is incorrect. %20 is specifically for representing the 0x20th Unicode character – that is “space”. It is not for representing other whitespace characters like tab (%09) etc. Tom Davie ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Mixing Obj-C and C methods
While all theses methods may look valid, what not simply use a static variable
declared in your file ?
Instead of trying to use complex approach to hide the fact you need a global,
just use one, and don't try to reuse the existing one for things there are not
designed to do.
static id myCallbackHandler;
void someCallBack() {
[myCallbackHandler handleCallBack];
}
- (void)foo {
myCallbackHandler = self;
callCFunctionWithCallBack(someCallBack);
myCallbackHandler = nil;
}
Le 30 juil. 2013 à 15:44, Maxthon Chan xcvi...@me.com a écrit :
My common way of handling this would be NSNotificationCenter. It is a
singleton so I am always sure that it is there, and I can wrap all parameters
into the userInfo dictionary.
Sent from my iPhone
On 2013年7月30日, at 21:19, KappA rejek...@gmail.com wrote:
I sometimes just access my objc-objects from a C thread-proc via the
AppDelegate (providing there's a trail to the object I need, which there
usually is)... If the callback void pointer parameter isn't being used for
something else, you can simply cast the object in there... or if you need
multiple parameters you can create a struct that stores what you need and
pass that. Not sure if this helps but figured I'd mention it.
AppDelegate *d = [[UIApplication sharedApplication] delegate];
On Tue, Jul 30, 2013 at 8:53 AM, lowell lowe...@me.com wrote:
The first two parameters to the function have to be an id and a SEL ...
typedef id (*IMP)(id, SEL, ...);
... (this is where we get self and _cmd, by the way) followed by the rest
of the method params, if any.
lowell
On Jul 30, 2013, at 12:59 AM, Vincent Habchi vi...@macports.org wrote:
Hi everybody,
I have a very simple question: if I embed a C-function (more precisely,
a callback from an external C-library) in an Obj-C object, can I expect
this function to behave like a regular method? I.e. can it freely access
‘self’ and other attributes?
Thanks a lot!
Vincent
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Re: Mixing Obj-C and C methods
Sorry, clicked a wrong button.
On Aug 7, 2013, at 16:00, Maxthon Chan xcvi...@me.com wrote:
Well here is a reason I think that is valid enough to implement a callback
using notifications: that is what Objective-C use for what callbacks used to
do, besides target-actions and delegations. In Cocoa, quite a lot of
delegated methods are actually mapped to messages.
Here is a snippet, with CGI as the class prefix:
void _CGI_SocketCallback(void *ctxt, int param)
{
id objectIdentifier = @((NSUInteger)ctxt); // Treat object pointers as
NSUIntegers - that prevents crashes and does not leak memory.
[[NSNotificationCenter defaultCenter]
postNotificationName:CGISocketNotification object:objectIdentifier
userData:@{@“param”: @(param)}];
}
- (void)setUpCallback
{
[[NSNotificationCenter defaultCenter] addObserver:self
action:@selector(callbackCalled:) name:CGISocketNotification
object:@((__bridge NSUInteger)self)];
}
If needed:
- (void)callbackCalled:(NSNotification *)aNotification
{
if ([self.delegate
respondsToSelector:@selector(connection:callbackDidCallWithParam:)])
[self.delegate connection:self
callbackDidCallWithParam:[aNotification userInfo][@“param”]];
}
On Aug 7, 2013, at 15:47, Jean-Daniel Dupas devli...@shadowlab.org wrote:
While all theses methods may look valid, what not simply use a static
variable declared in your file ?
Instead of trying to use complex approach to hide the fact you need a
global, just use one, and don't try to reuse the existing one for things
there are not designed to do.
static id myCallbackHandler;
void someCallBack() {
[myCallbackHandler handleCallBack];
}
- (void)foo {
myCallbackHandler = self;
callCFunctionWithCallBack(someCallBack);
myCallbackHandler = nil;
}
Le 30 juil. 2013 à 15:44, Maxthon Chan xcvi...@me.com a écrit :
My common way of handling this would be NSNotificationCenter. It is a
singleton so I am always sure that it is there, and I can wrap all
parameters into the userInfo dictionary.
Sent from my iPhone
On 2013年7月30日, at 21:19, KappA rejek...@gmail.com wrote:
I sometimes just access my objc-objects from a C thread-proc via the
AppDelegate (providing there's a trail to the object I need, which there
usually is)... If the callback void pointer parameter isn't being used for
something else, you can simply cast the object in there... or if you need
multiple parameters you can create a struct that stores what you need and
pass that. Not sure if this helps but figured I'd mention it.
AppDelegate *d = [[UIApplication sharedApplication] delegate];
On Tue, Jul 30, 2013 at 8:53 AM, lowell lowe...@me.com wrote:
The first two parameters to the function have to be an id and a SEL ...
typedef id (*IMP)(id, SEL, ...);
... (this is where we get self and _cmd, by the way) followed by the rest
of the method params, if any.
lowell
On Jul 30, 2013, at 12:59 AM, Vincent Habchi vi...@macports.org wrote:
Hi everybody,
I have a very simple question: if I embed a C-function (more precisely,
a callback from an external C-library) in an Obj-C object, can I expect
this function to behave like a regular method? I.e. can it freely access
‘self’ and other attributes?
Thanks a lot!
Vincent
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Re: Mixing Obj-C and C methods
On Aug 7, 2013, at 1:47 AM, Jean-Daniel Dupas devli...@shadowlab.org wrote: While all theses methods may look valid, what not simply use a static variable declared in your file ? DING DING DING DING! WE HAVE A WINNER! Actually, much of the history behind other methods for singletons revolves around big enterprisey nasty inter-tangled systems where developers lose track of (in many cases, never knew in the first place) the dependencies between globals. Well, in my opinion, if you have so many dependencies between globals that you can't figure out in which order to initialize them, you have a far bigger problem. -- Scott Ribe scott_r...@elevated-dev.com http://www.elevated-dev.com/ (303) 722-0567 voice ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Synchronous Serial Port Protocol messaging With NSOperationQueue/GCD
On Thu, 1 Aug 2013 12:03:01 +0200, Vanni Parronchi said: hi everyone, I'm writing a mac osx app that needs to talk to a serial device. Have you considered using the open source AMSerialPort class? It doesn't use GCD, but does have an NSThread option. It could probably be retrofitted to use GCD also... which I have been thinking I might one day have time to do... Cheers, -- Sean McBride, B. Eng s...@rogue-research.com Rogue Researchwww.rogue-research.com Mac Software Developer Montréal, Québec, Canada ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Mixing Obj-C and C methods
On Aug 7, 2013, at 3:47 AM, Jean-Daniel Dupas devli...@shadowlab.org wrote:
Instead of trying to use complex approach to hide the fact you need a global,
just use one, and don't try to reuse the existing one for things there are
not designed to do.
static id myCallbackHandler;
void someCallBack() {
[myCallbackHandler handleCallBack];
}
- (void)foo {
myCallbackHandler = self;
callCFunctionWithCallBack(someCallBack);
myCallbackHandler = nil;
}
What if instance x does [x foo], and before someCallBack() gets called, some
other instance y does [y foo]? There will be two future calls to
someCallBack(), and [y handleCallBack] will be called both times, which is not
the desired outcome. This is a problem with any approach where the callback
looks in some global place, whether it's a static variable, a key path from the
app delegate, or whatever.
Even if you are sure you won't run into the problem of the global variable
being overwritten, I think routing self through a global like myCallbackHandler
is more complex than:
void someCallBack(void *contextPtr) {
[[(MyClass *)contextPtr autorelease] handleCallBack];
}
- (void)foo {
callCFunctionWithCallBack(someCallBack, (void *)[self retain]);
}
or with ARC:
void someCallBack(void *contextPtr) {
[(__bridge_retained MyClass *)contextPtr handleCallBack];
}
- (void)foo {
callCFunctionWithCallBack(someCallBack, (__bridge_transfer void *)self);
}
This assumes that the API includes a context pointer, but realistically, how
often won't that be the case? (I don't actually know.)
--Andy
Le 30 juil. 2013 à 15:44, Maxthon Chan xcvi...@me.com a écrit :
My common way of handling this would be NSNotificationCenter. It is a
singleton so I am always sure that it is there, and I can wrap all
parameters into the userInfo dictionary.
Sent from my iPhone
On 2013年7月30日, at 21:19, KappA rejek...@gmail.com wrote:
I sometimes just access my objc-objects from a C thread-proc via the
AppDelegate (providing there's a trail to the object I need, which there
usually is)... If the callback void pointer parameter isn't being used for
something else, you can simply cast the object in there... or if you need
multiple parameters you can create a struct that stores what you need and
pass that. Not sure if this helps but figured I'd mention it.
AppDelegate *d = [[UIApplication sharedApplication] delegate];
On Tue, Jul 30, 2013 at 8:53 AM, lowell lowe...@me.com wrote:
The first two parameters to the function have to be an id and a SEL ...
typedef id (*IMP)(id, SEL, ...);
... (this is where we get self and _cmd, by the way) followed by the rest
of the method params, if any.
lowell
On Jul 30, 2013, at 12:59 AM, Vincent Habchi vi...@macports.org wrote:
Hi everybody,
I have a very simple question: if I embed a C-function (more precisely,
a callback from an external C-library) in an Obj-C object, can I expect
this function to behave like a regular method? I.e. can it freely access
‘self’ and other attributes?
Thanks a lot!
Vincent
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Re: Synchronous Serial Port Protocol messaging With NSOperationQueue/GCD
On Aug 7, 2013, at 2:20 AM, Tom Davie wrote: My suggestion would instead be to make an NSOperation subclass for sending a message to the device. That subclass should require you to specify to which device you are talking. Each device object should carry around a dispatch_semaphore. When a message is sent, the semaphore should be checked and set to stop any other operations proceeding until the semaphore is unset. When the device responds, the semaphore should be unset. You can then make your operation queue a concurrent queue, rather than a serial one, so that you can send messages to more than one device at the same time, while still maintaining your one-thing-at-a-time per device rule. Why would you do that? Operation queues are cheap. Have one serial queue per device. There's little reason to add another synchronization method on top of operations to cause them to serialize with respect to one another. Regards, Ken ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Mixing Obj-C and C methods
Le 7 août 2013 à 17:32, Andy Lee ag...@mac.com a écrit :
On Aug 7, 2013, at 3:47 AM, Jean-Daniel Dupas devli...@shadowlab.org wrote:
Instead of trying to use complex approach to hide the fact you need a
global, just use one, and don't try to reuse the existing one for things
there are not designed to do.
static id myCallbackHandler;
void someCallBack() {
[myCallbackHandler handleCallBack];
}
- (void)foo {
myCallbackHandler = self;
callCFunctionWithCallBack(someCallBack);
myCallbackHandler = nil;
}
What if instance x does [x foo], and before someCallBack() gets called, some
other instance y does [y foo]? There will be two future calls to
someCallBack(), and [y handleCallBack] will be called both times, which is
not the desired outcome. This is a problem with any approach where the
callback looks in some global place, whether it's a static variable, a key
path from the app delegate, or whatever.
Even if you are sure you won't run into the problem of the global variable
being overwritten, I think routing self through a global like
myCallbackHandler is more complex than:
If you intend to use it from multiple threads, so use a tls.
__thread id myCallbackHandler;
I was talking about the case where you have to deal with a poorly design API
with no context pointer argument.
The case with a context argument should off course be handle the way you
describe.
void someCallBack(void *contextPtr) {
[[(MyClass *)contextPtr autorelease] handleCallBack];
}
- (void)foo {
callCFunctionWithCallBack(someCallBack, (void *)[self retain]);
}
or with ARC:
void someCallBack(void *contextPtr) {
[(__bridge_retained MyClass *)contextPtr handleCallBack];
}
- (void)foo {
callCFunctionWithCallBack(someCallBack, (__bridge_transfer void *)self);
}
This assumes that the API includes a context pointer, but realistically, how
often won't that be the case? (I don't actually know.)
--Andy
Le 30 juil. 2013 à 15:44, Maxthon Chan xcvi...@me.com a écrit :
My common way of handling this would be NSNotificationCenter. It is a
singleton so I am always sure that it is there, and I can wrap all
parameters into the userInfo dictionary.
Sent from my iPhone
On 2013年7月30日, at 21:19, KappA rejek...@gmail.com wrote:
I sometimes just access my objc-objects from a C thread-proc via the
AppDelegate (providing there's a trail to the object I need, which there
usually is)... If the callback void pointer parameter isn't being used for
something else, you can simply cast the object in there... or if you need
multiple parameters you can create a struct that stores what you need and
pass that. Not sure if this helps but figured I'd mention it.
AppDelegate *d = [[UIApplication sharedApplication] delegate];
On Tue, Jul 30, 2013 at 8:53 AM, lowell lowe...@me.com wrote:
The first two parameters to the function have to be an id and a SEL ...
typedef id (*IMP)(id, SEL, ...);
... (this is where we get self and _cmd, by the way) followed by the rest
of the method params, if any.
lowell
On Jul 30, 2013, at 12:59 AM, Vincent Habchi vi...@macports.org wrote:
Hi everybody,
I have a very simple question: if I embed a C-function (more precisely,
a callback from an external C-library) in an Obj-C object, can I expect
this function to behave like a regular method? I.e. can it freely access
‘self’ and other attributes?
Thanks a lot!
Vincent
-- Jean-Daniel
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Re: Mixing Obj-C and C methods
On Aug 7, 2013, at 12:04 PM, Jean-Daniel Dupas devli...@shadowlab.org wrote: If you intend to use it from multiple threads, so use a tls. __thread id myCallbackHandler; I did not know about __thread, thanks for this. By using tls you're effectively having each thread store the info that would have been stored by the implementation of the callback's context pointer, if it had one. If [x foo] and [y foo] are called in the same thread, then that thread's myCallbackHandler can still get clobbered if the callback is asynchronous. So I guess you'd have to be careful to always call -foo in a separate thread, or implement it to always spawn a thread. I was talking about the case where you have to deal with a poorly design API with no context pointer argument. The case with a context argument should off course be handle the way you describe. I see, thanks. --Andy ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Mixing Obj-C and C methods
Le 7 août 2013 à 18:34, Andy Lee ag...@mac.com a écrit : On Aug 7, 2013, at 12:04 PM, Jean-Daniel Dupas devli...@shadowlab.org wrote: If you intend to use it from multiple threads, so use a tls. __thread id myCallbackHandler; I did not know about __thread, thanks for this. By using tls you're effectively having each thread store the info that would have been stored by the implementation of the callback's context pointer, if it had one. If [x foo] and [y foo] are called in the same thread, then that thread's myCallbackHandler can still get clobbered if the callback is asynchronous. So I guess you'd have to be careful to always call -foo in a separate thread, or implement it to always spawn a thread. And even with a synchronous API, the TLS approach is fragile as the API as to guarantee that the callback is performed on the same thread. But honestly, if I encounter such API and it does not let me pass a context pointer for the callback, I will just avoid it and use something else. I was talking about the case where you have to deal with a poorly design API with no context pointer argument. The case with a context argument should off course be handle the way you describe. I see, thanks. --Andy -- Jean-Daniel ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: Synchronous Serial Port Protocol messaging With NSOperationQueue/GCD
Hi all, Thank you all for you contribution and responses. It was my first message to the list and was a bit intimidated :). the app is meant to be modular, 10.7 based and it has to manage not only serial devices (rs485) but also USB ones (through a virtual com port using an FTDI chip on the device and an external C library some contractor made quite some time ago for the company i'm working for, that abstracts communication with the FTDI underlying driver). I'm focusing on the serial ones for now. given the modular nature the app uses loadable bundles as plugins so that every plugin can be updated independently (i'm thinking about using the famous sparkle http://sparkle.andymatuschak.org/%E2%80%8E by Andy Matuschak, anyone?). I've managed to implement a kind of IOC/service locatorhttp://www.martinfowler.com/articles/injection.html#UsingAServiceLocatorin a framework that every bundle can have access to, in order to request instances belonging to different bundles through protocols. And for messaging to/from bundles i made use of NSNotificationCenter a lot, probably abusing it, hoping that this won't bring issues in the future. Those serial devices can be daisy chained together, every device has a unique integer ID that can be set on the device Every command sent to the device is an instance of a high level message class that encapsulates all the information a message has to have (target device id, command and data) The connection layer plugins (rs485, usb) are abstracted through proper class (loadable bundle) and every class *has* a message manager that receives high level messages and converts to/from low level messages in form of pure NSData objects. Through a category on NSData i can factorize a high level message in the proper set of bytes, then send the NSData to serial port and wait for the response (if no response every message has a timeout) I can't talk to different devices at the same time because collisions on the bus can happen thus corrupting the messages. It has to be strictly half duplex I use ORSSerialPort as the serial port library. I found its API to be more comfortable than the AMSerialPort i tried when i started. NSOperation and NSOperationQueues enables you to better encapsulate the logic of sending a message, but at the end all the messages are not so different in term if implementation at a lower level and the balance between encapsulating but passing lots of arguments and handling everything in a dispatch call preserving scope and context led me to go with pure GCD. I use dispatch_groups to handle high level commands that are in fact the product of several low level messages to the device, dispatch_async and dispatch_semaphore to wait for the response, and i also fire a dispatch_source with a timer to handle timeouts, i.e. discovering devices from the software implies firing messages to integer IDs in a for loop. So far, seems that the synchronization is achieved but i'll see when i'll go further. It's my first app for Mac OS X, i did entirely iOS before, and i've run through so much trials and errors that i almost burned out. Hope i'll get it to be shipped. For those who managed to read all this, does it seem a reasonable approach to the problem? Thank you and Best Regards! Vanni 2013/8/7 Ken Thomases k...@codeweavers.com On Aug 7, 2013, at 2:20 AM, Tom Davie wrote: My suggestion would instead be to make an NSOperation subclass for sending a message to the device. That subclass should require you to specify to which device you are talking. Each device object should carry around a dispatch_semaphore. When a message is sent, the semaphore should be checked and set to stop any other operations proceeding until the semaphore is unset. When the device responds, the semaphore should be unset. You can then make your operation queue a concurrent queue, rather than a serial one, so that you can send messages to more than one device at the same time, while still maintaining your one-thing-at-a-time per device rule. Why would you do that? Operation queues are cheap. Have one serial queue per device. There's little reason to add another synchronization method on top of operations to cause them to serialize with respect to one another. Regards, Ken ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
IOS floating point performance
I have an app that is running slow. I have narrowed it down to several functions which are trig-intensive (used to calculate the position of the moon at a given moment and more specifically to calculate rise/set times). To calculate the position and rise/set times for a month on average, requires: 300 trig functions for position 24 points in time to find the correct set of three points 30 days 2 events Total of 432,000 trig functions (mostly sin and cos) On my iPad 3, this takes about 3 seconds, and on my desktop (2.3GHz Quad-core i7) it is nearly instantaneous. I am using doubles (not floats). What can I do to speed this up? ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: IOS floating point performance
A few things: - The little ARM in the iPad 3 is nothing compared to your desktop. Not only is it not as fast, it doesn't have the memory bandwidth. Also, an iPad 4 will be twice as fast. - make sure you're running optimized code. You can set optimization flags on individual files (that's what I do in our compute-heavy code, so I can run debug releases for the UI but leave the computation optimized). - Find a way to compute less. Algorithmic optimizations are key here. Maybe a larger step size? - Can you break up the work into multiple tasks? That will allow you to parallelize the work. At the very least, make sure you're doing it on a separate dispatch queue/NSOperationQueue so it doesn't block your main UI. On Aug 7, 2013, at 13:50 , Trygve Inda cocoa...@xericdesign.com wrote: I have an app that is running slow. I have narrowed it down to several functions which are trig-intensive (used to calculate the position of the moon at a given moment and more specifically to calculate rise/set times). To calculate the position and rise/set times for a month on average, requires: 300 trig functions for position 24 points in time to find the correct set of three points 30 days 2 events Total of 432,000 trig functions (mostly sin and cos) On my iPad 3, this takes about 3 seconds, and on my desktop (2.3GHz Quad-core i7) it is nearly instantaneous. I am using doubles (not floats). What can I do to speed this up? ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/rmann%40latencyzero.com This email sent to rm...@latencyzero.com -- Rick ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: IOS floating point performance
On 7 Aug 2013, at 3:50 PM, Trygve Inda cocoa...@xericdesign.com wrote: I have an app that is running slow. I have narrowed it down to several functions which are trig-intensive (used to calculate the position of the moon at a given moment and more specifically to calculate rise/set times). To calculate the position and rise/set times for a month on average, requires: 300 trig functions for position 24 points in time to find the correct set of three points 30 days 2 events Total of 432,000 trig functions (mostly sin and cos) On my iPad 3, this takes about 3 seconds, and on my desktop (2.3GHz Quad-core i7) it is nearly instantaneous. I am using doubles (not floats). What can I do to speed this up? You don't have to be told that desktop performance with the same algorithm on a processor that is 1-10% as fast isn't going to happen. If you can figure out how to vectorize your calculations, look at veclib in the Accelerate framework. vvsin() and vvsinf() have been available since iOS 5. I'm a little surprised to see that veclib supports doubles. My instinct (based on imagining that you'll be striding through an array with vector registers that can hold two doubles or four floats)* is that floats could be much faster, and you should really think about whether you need doubles: You're depicting the moon, not flying there. * (Readers should consider whether correcting my rule-of-thumb notion is a good use of their time.) — F ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: IOS floating point performance
On Aug 7, 2013, at 1:50 PM, Trygve Inda cocoa...@xericdesign.com wrote: I have an app that is running slow. I have narrowed it down to several functions which are trig-intensive (used to calculate the position of the moon at a given moment and more specifically to calculate rise/set times). To calculate the position and rise/set times for a month on average, requires: 300 trig functions for position 24 points in time to find the correct set of three points 30 days 2 events Total of 432,000 trig functions (mostly sin and cos) On my iPad 3, this takes about 3 seconds, and on my desktop (2.3GHz Quad-core i7) it is nearly instantaneous. I am using doubles (not floats). What can I do to speed this up? This is somewhat outside my area of expertise, but if your calculations are at least partially independent, and can thus be expressed in terms of vector calculations, then you might take a look at vecLib (part of Accelerate.framework), https://developer.apple.com/library/ios/#documentation/Performance/Conceptual/vecLib/Reference/reference.html There’s also a WWDC session from 2011 or 2012 that provides an introduction to Accelerate.framework. -Conrad ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: IOS floating point performance
A few things: - The little ARM in the iPad 3 is nothing compared to your desktop. Not only is it not as fast, it doesn't have the memory bandwidth. Also, an iPad 4 will be twice as fast. - make sure you're running optimized code. You can set optimization flags on individual files (that's what I do in our compute-heavy code, so I can run debug releases for the UI but leave the computation optimized). - Find a way to compute less. Algorithmic optimizations are key here. Maybe a larger step size? - Can you break up the work into multiple tasks? That will allow you to parallelize the work. At the very least, make sure you're doing it on a separate dispatch queue/NSOperationQueue so it doesn't block your main UI. I am currently doing it on an NSThread. I may try replacing all the doubles with floats in the algorithm and see how that goes (on a backup of course!). How do I set optimization on a per-file basis? Trygve ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: IOS floating point performance
On Aug 7, 2013, at 14:34 , Trygve Inda cocoa...@xericdesign.com wrote: I am currently doing it on an NSThread. I may try replacing all the doubles with floats in the algorithm and see how that goes (on a backup of course!). Yes, floats should help (unless precision errors make it worse). You'll be moving a lot less memory around, and they're computed in hardware (I think double requires software intervention, but I could be wrong about that). How do I set optimization on a per-file basis? In the Target settings, Build Phases tab, Compile Sources phase, you can set individual compiler flags. I put -O3 on each of the files I want optimized. -O2 or -Os should be tried, too, to see which gives you the best results. -- Rick ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: IOS floating point performance
On Aug 7, 2013, at 2:27 PM, Fritz Anderson wrote: On 7 Aug 2013, at 3:50 PM, Trygve Inda cocoa...@xericdesign.com wrote: I have an app that is running slow. I have narrowed it down to several functions which are trig-intensive (used to calculate the position of the moon at a given moment and more specifically to calculate rise/set times). To calculate the position and rise/set times for a month on average, requires: 300 trig functions for position 24 points in time to find the correct set of three points 30 days 2 events Total of 432,000 trig functions (mostly sin and cos) On my iPad 3, this takes about 3 seconds, and on my desktop (2.3GHz Quad-core i7) it is nearly instantaneous. I am using doubles (not floats). What can I do to speed this up? You don't have to be told that desktop performance with the same algorithm on a processor that is 1-10% as fast isn't going to happen. If you can figure out how to vectorize your calculations, look at veclib in the Accelerate framework. vvsin() and vvsinf() have been available since iOS 5. I'm a little surprised to see that veclib supports doubles. My instinct (based on imagining that you'll be striding through an array with vector registers that can hold two doubles or four floats)* is that floats could be much faster, and you should really think about whether you need doubles: You're depicting the moon, not flying there. * (Readers should consider whether correcting my rule-of-thumb notion is a good use of their time.) — F You can also use lookup tables for your trig functions, especially if you can live with less precision. And you can look and see if there are calculations that are going to be repeated, and do those only once (or once per loop, as appropriate). Also, you might be able to combine some of the calculations into simpler ones, using the rules of trig (think sin2x, etc.). Another approach is to represent sines and cosines as infinite series, and combine those series in order to compute one (or two, or a few) series that you can then either compute directly (using finite approximations to the infinite series) or turn them back into trig functions. (That's difficult work, though, far beyond just using trig functions.) -Howard ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: IOS floating point performance
I'm a little surprised to see that veclib supports doubles. My instinct (based on imagining that you'll be striding through an array with vector registers that can hold two doubles or four floats)* is that floats could be much faster, and you should really think about whether you need doubles: You're depicting the moon, not flying there. Floats don't work - I get completely wrong results. Trygve ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: IOS floating point performance
On Aug 7, 2013, at 14:34 , Trygve Inda cocoa...@xericdesign.com wrote: I am currently doing it on an NSThread. I may try replacing all the doubles with floats in the algorithm and see how that goes (on a backup of course!). Yes, floats should help (unless precision errors make it worse). You'll be moving a lot less memory around, and they're computed in hardware (I think double requires software intervention, but I could be wrong about that). How do I set optimization on a per-file basis? In the Target settings, Build Phases tab, Compile Sources phase, you can set individual compiler flags. I put -O3 on each of the files I want optimized. -O2 or -Os should be tried, too, to see which gives you the best results. I tried using floats and the results were wrong, presumably due to lower precision and compounding of errors (but it took roughly the same amount of time as doubles). ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: IOS floating point performance
I have written an app that does astronomical calculations like that , Sun and Moon rise and set and location and….. I never saw a problem with speed. I was very impressed with how much it can do. However, are you using Objective C methods for the calculations? The run time dispatch in Objective C could slow things considerably. I wrote all my math in C++. David On Aug 7, 2013, at 1:50 PM, Trygve Inda cocoa...@xericdesign.com wrote: I have an app that is running slow. I have narrowed it down to several functions which are trig-intensive (used to calculate the position of the moon at a given moment and more specifically to calculate rise/set times). To calculate the position and rise/set times for a month on average, requires: 300 trig functions for position 24 points in time to find the correct set of three points 30 days 2 events Total of 432,000 trig functions (mostly sin and cos) On my iPad 3, this takes about 3 seconds, and on my desktop (2.3GHz Quad-core i7) it is nearly instantaneous. I am using doubles (not floats). What can I do to speed this up? ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/rowlandd%40sbcglobal.net This email sent to rowla...@sbcglobal.net ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: IOS floating point performance
I have written an app that does astronomical calculations like that , Sun and Moon rise and set and location and….. I never saw a problem with speed. I was very impressed with how much it can do. However, are you using Objective C methods for the calculations? The run time dispatch in Objective C could slow things considerably. I wrote all my math in C++. David I am using C for the math calcs. The issue is I am trying to calc a month at a time... Sun rise/set and moon rise/set for 30 days. For one day it is plenty fast, but the slow speed shows up when doing a month at a time. Did you use floats or doubles? Trygve ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
Re: IOS floating point performance
On Aug 7, 2013, at 1:50 PM, Trygve Inda cocoa...@xericdesign.com wrote: What can I do to speed this up? Did you use Instruments to CPU-profile the app? It would be a good idea, at least to confirm that the slowness comes directly from the math functions and not something else like memory allocation or method-dispatching. —Jens ___ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
