Re: dispatch_source does not work
Re: dispatch_source does not work
- Subject: Re: dispatch_source does not work
- From: Peter <email@hidden>
- Date: Wed, 05 Nov 2014 08:08:52 +0100
http://stackoverflow.com/questions/12343833/cocoa-monitor-a-file-for-modifications/26304208#26304208
has some info on this.
___ Peter Hartmann ________
mailto:email@hidden
Am 05.11.2014 um 07:50 schrieb Gerriet M. Denkmann <email@hidden>:
> I want to monitor a file for changed content.
> Polling is generally not a good idea, so I tried dispatch_source.
>
> But it does not work.
>
> Here the code:
>
> static NSString *const kTestPath = @"/tmp/a.test";
>
> - (void)applicationDidFinishLaunching:(NSNotification *)aNotification
> {
> const char *filename = kTestPath.fileSystemRepresentation;
> int fd = open(filename, O_RDONLY);
> fcntl(fd, F_SETFL, O_NONBLOCK);
> uintptr_t fD = (uintptr_t)fd;
> dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
> const uint64_t flags = DISPATCH_VNODE_WRITE | DISPATCH_VNODE_LINK;
> dispatch_source_t my_source = dispatch_source_create(DISPATCH_SOURCE_TYPE_VNODE, fD, flags, queue);
> dispatch_source_set_event_handler(my_source, ^{ [self fileDidChange]; } );
> dispatch_resume(my_source);
> }
>
> - (void)fileDidChange
> {
> NSLog(@"%s",__FUNCTION__); // never seen
> }
>
> - (IBAction)buttonClicked: sender
> {
> static NSUInteger seqq = 0;
> seqq++;
>
> const char *stats_temp_file = "/tmp/a.temp";
> FILE *fp = fopen(stats_temp_file, "w");
> fprintf(fp, "%lu\n", seqq);
> (void)fclose(fp);
>
> const char *filename = kTestPath.fileSystemRepresentation;
> int a = rename(stats_temp_file, filename);
> }
>
> What am I doing wrong? (Writing directly to kTestPath without rename() also does not work).
>
> Gerriet.
>
>
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