examples/Dispatch Samples/timers.c

   1 /*
   2  * Copyright (c) 2008 Apple Inc.  All rights reserved.
   3  *
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   6  * IMPORTANT:  This Apple software is supplied to you by Apple Computer, Inc.
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  10  * please do not use, install, modify or redistribute this Apple software.
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  12  * In consideration of your agreement to abide by the following terms, and
  13  * subject to these terms, Apple grants you a personal, non-exclusive license,
  14  * under Apple's copyrights in this original Apple software (the "Apple Software"),
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  27  * The Apple Software is provided by Apple on an "AS IS" basis.  APPLE MAKES NO
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  42  */
  43
  44 #include <assert.h>
  45 #include <stdio.h>
  46 #include <string.h>
  47 #include <stdlib.h>
  48 #include <sys/errno.h>
  49 #include <mach/clock_types.h>
  50
  51 #include <dispatch/dispatch.h>
  52
  53 int main(int argc, char* argv[])
  54 {
  55         dispatch_source_t theTimer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, dispatch_queue_create("timer queue",NULL));
  56
  57         __block int i = 0;
  58
  59         printf("Starting to count by seconds\n");
  60
  61         dispatch_source_set_event_handler(theTimer, ^{
  62                         printf("%d\n", ++i);
  63                         if (i >= 6) {
  64                                 printf("i>6\n");
  65                                 dispatch_source_cancel(theTimer);
  66                         }
  67                         if (i == 3) {
  68                                 printf("switching to half seconds\n");
  69                                 dispatch_source_set_timer(theTimer, DISPATCH_TIME_NOW, NSEC_PER_SEC / 2, 0);
  70                         }
  71         });
  72
  73         dispatch_source_set_cancel_handler(theTimer, ^{
  74                 printf("dispatch source canceled OK\n");
  75                 dispatch_release(theTimer);
  76                 exit(0);
  77         });
  78
  79         dispatch_source_set_timer(theTimer, dispatch_time(DISPATCH_TIME_NOW,NSEC_PER_SEC) , NSEC_PER_SEC, 0);
  80
  81         dispatch_resume(theTimer);
  82         dispatch_main();
  83
  84         return 0;
  85 }