IOBluetoothDevice openConnection失败 - 识别错误代码

我在写一个使用蓝牙的Cocoa应用程序。我正尝试连接到蓝牙设备，但失败。IOBluetoothDevice openConnection失败 - 识别错误代码

IOBluetoothDevice *btDevice; 

// I do search and find the device 
btDevice = ;//device found 
//btDevice is not nil 

IOReturn status   = [btDevice openConnection]; 
if (status != kIOReturnSuccess) { 
    NSLog(@"Error - failed to connect. %d", status); 
}

我什么时候搜索获得设备，但openConnection方法失败。和NSLog打印

错误=无法连接。 4

现在这个错误代码表示什么？我看着IOKit.framework/IOReturn.h文件，它显示了许多错误代码

#define kIOReturnError   iokit_common_err(0x2bc) // general error 
#define kIOReturnNoMemory  iokit_common_err(0x2bd) // can't allocate memory 
#define kIOReturnNoResources  iokit_common_err(0x2be) // resource shortage 
#define kIOReturnIPCError  iokit_common_err(0x2bf) // error during IPC 
#define kIOReturnNoDevice  iokit_common_err(0x2c0) // no such device 
....... 
//And many more

我写一个函数来确定哪些是错误代码4

- (void)logError:(OSStatus)status{ 
    if (status == kIOReturnError) { 
     NSLog(@"kIOReturnError"); 
    }else if(status == kIOReturnNoMemory){ 
     NSLog(@"kIOReturnNoMemory"); 
    }else if(status == kIOReturnNoResources){ 
     NSLog(@"kIOReturnNoResources"); 
    }else if(status == kIOReturnIPCError){ 
     NSLog(@"kIOReturnIPCError"); 
    }else if(status == kIOReturnNoDevice){ 
    ...... 
    ...... 
    }else{ 
     NSLog(@"No price for you"); 
    } 
}

而且它打印