IOBluetoothDevice openConnection失敗 - 識別錯誤代碼

我在寫一個使用藍牙的Cocoa應用程序。我正嘗試連接到藍牙設備，但失敗。IOBluetoothDevice openConnection失敗 - 識別錯誤代碼

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); 
}

我什麼時候搜索獲得設備，但openConnection方法失敗。和NSLog打印

錯誤=無法連接。 4

現在這個錯誤代碼表示什麼？我看着IOKit.framework/IOReturn.h文件，它顯示了許多錯誤代碼

#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

我寫一個函數來確定哪些是錯誤代碼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