Question

所以，我有一个应用程序可以进行大量数学运算，但是当我使用Global Dispatch Queue进行多线程时它只会崩溃。我想我可能做错了。任何人都可以解释为什么这会导致崩溃？或者至少我可以尝试调试它。

如果我这样做，它打印出答案很好。我用仪器查看了代码，它没有泄漏或任何东西。

NSStringEncoding encoding;
NSError *error;

//Read in data file
NSString *Data1FileContent = [NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"data1" ofType:@"txt"] usedEncoding:&encoding error:&error];
NSMutableArray *strides = [[Data1FileContent componentsSeparatedByString:@"\n"] mutableCopy];

//Read in data file
NSString *Data2FileContent = [NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"data2" ofType:@"txt"] usedEncoding:&encoding error:&error];
NSMutableArray *gaitTimes = [[Data2FileContent componentsSeparatedByString:@"\n"] mutableCopy];

//Math
NSMutableArray *result = [gaitlyapunov gaitlyapunov:strides withTimeSteps:gaitTimes withFreq:150 withSegmentApproach:@"strides"];

NSLog(@"result = %@", result);

[gaitTimes release];
[strides release];

});

但是，当我尝试更新代码中的UILabel时，会导致崩溃。

错误：

(lldb) //Thrown randomly in the math

导致问题的代码：

//Create a queue
dispatch_async(dispatch_get_global_queue(0, 0), ^{

    //This prints out fine
    dispatch_async(dispatch_get_main_queue(), ^{
        statusText.text = [NSString stringWithFormat:@"processing..."];
    });


NSStringEncoding encoding;
NSError *error;

//Read data
NSString *Data1FileContent = [NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"data1" ofType:@"txt"] usedEncoding:&encoding error:&error];
NSMutableArray *strides = [[Data1FileContent componentsSeparatedByString:@"\n"] mutableCopy];

//Read data
NSString *Data2FileContent = [NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"data2" ofType:@"txt"] usedEncoding:&encoding error:&error];
NSMutableArray *gaitTimes = [[Data2FileContent componentsSeparatedByString:@"\n"] mutableCopy];

//Math, that causes crash in this code only
NSMutableArray *result = [gaitlyapunov gaitlyapunov:strides withTimeSteps:gaitTimes withFreq:150 withSegmentApproach:@"strides"];

    //This should print the result into the label
    dispatch_async(dispatch_get_main_queue(), ^{
            statusText.text = [NSString stringWithFormat: @"result: %@", result];
    });

[gaitTimes release];
[strides release];

});

Answer 1

我将我的问题跟踪到非线程安全编程问题。有关详细信息，请参阅此处：https://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/Multithreading/ThreadSafetySummary/ThreadSafetySummary.html。

调度全局队列崩溃

1 个答案: