IOS thread lock example

A: Resource lock

#import <GHUnitIOS/GHUnit.h> 

@interface WPGlobalTest : GHTestCase{    int         _count;    NSLock      *_lock;}@end

-(void)test3{    if (_lock == nil) {        _lock = [[NSLock alloc] init];    }        NSThread *t1 = [[[NSThread alloc] initWithTarget:self selector:@selector(run) object:nil] autorelease];     [t1 setName:@"t1"];    [t1 start];        NSThread *t2 = [[[NSThread alloc] initWithTarget:self selector:@selector(run) object:nil] autorelease];     [t2 setName:@"t2"];    [t2 start];        NSThread *t3 = [[[NSThread alloc] initWithTarget:self selector:@selector(run) object:nil] autorelease];     [t3 setName:@"t3"];    [t3 start];    }-(void)run{    NSAutoreleasePool *aPool = [[NSAutoreleasePool alloc] init];    while (1) {        //[_lock lock];        _count++;        NSThread *currentThread = [NSThread currentThread];        NSLog(@"current thread name -> %@, count -> %d", [currentThread name], _count);        [NSThread sleepForTimeInterval:1];        //[_lock unlock];    }    [aPool drain];}@end

There is no lock (Comment [_ lock] and [_ Lock unlock]), the resource (_ count) will conflict.

13:20:14. 340 tests [7526: 14903] current thread name-> T3, Count-> 10

13:20:14. 340 tests [7526: 14403] current thread name-> T2, Count-> 11

13:20:14. 340 tests [7526: 14103] current thread name-> T1, Count-> 10

13:20:15. 343 tests [7526: 14403] current thread name-> T2, Count-> 13

13:20:15. 343 tests [7526: 14903] current thread name-> T3, Count-> 12

13:20:15. 343 tests [7526: 14103] current thread name-> T1, Count-> 12

13:20:16. 347 tests [7526: 14903] current thread name-> T3, Count-> 15

13:20:16. 347 tests [7526: 14103] current thread name-> T1, Count-> 14

13:20:16. 347 tests [7526: 14403] current thread name-> T2, Count-> 14

Resources do not conflict after the lock is applied.

13:23:53. 325 tests [7639: 14103] current thread name-> T1, Count-> 1

13:23:53. 326 tests [7639: 10703] wpglobaltest/test3 0.00 s

13:23:54. 327 tests [7639: 14403] current thread name-> T2, Count-> 2

13:23:55. 329 tests [7639: 14b03] current thread name-> T3, Count-> 3

13:23:56. 332 tests [7639: 14103] current thread name-> T1, Count-> 4

13:23:57. 334 tests [7639: 14403] current thread name-> T2, Count-> 5

13:23:58. 337 tests [7639: 14b03] current thread name-> T3, Count-> 6

13:23:59. 339 tests [7639: 14103] current thread name-> T1, Count-> 7

13:24:00. 340 tests [7639: 14403] current thread name-> T2, Count-> 8

13:24:01. 343 tests [7639: 14b03] current thread name-> T3, Count-> 9

B: Conditional lock example

# Import <ghunitios/ghunit. h> @ interface wpglobaltest: ghtestcase {int _ count; nslock * _ Lock; // resource lock nscondition * _ condition; // condition lock bool _ isok;} @ end

-(Void) test4 {If (_ condition = nil) {_ condition = [[nscondition alloc] init]; _ isok = no;} [nsthread detachnewthreadselector: @ selector (run1) totarget: Self withobject: Nil]; [nsthread sleepfortimeinterval: 10]; [nsthread detachnewthreadselector: @ selector (run2) totarget: Self withobject: Nil];} -(void) run1 {nslog (@ "Start run1... "); [_ condition lock]; // lock while (! _ Isok) {nslog (@ "run1 waiting... "); [_ condition Wait];} [_ condition unlock]; nslog (@" Stop run1... ");}-(void) run2 {nslog (@" Start run2... "); [_ condition lock]; _ isok = yes; nslog (@" change value... "); [_ condition signal]; nslog (@" signal run2... "); [_ condition unlock]; nslog (@" Stop run2... ");} @ end

Result:

14:17:32. 548 tests [9044: 14103] Start run1...

14:17:32. 549 tests [9044: 14103] run1 waiting...

14:17:42. 549 tests [9044: 12407] Start run2...

14:17:42. 550 tests [9044: 12407] change value...

14:17:42. 550 tests [9044: 10703] wpglobaltest/test4 10.00 s

14:17:42. 552 tests [9044: 12407] signal run2...

14:17:42. 553 tests [9044: 14103] Stop run1...

14:17:42. 553 tests [9044: 12407] Stop run2...