集成百度地图SDK，按照文档设置之后，运行报错。

Undefined symbols for architecture x86_64:
  "_OBJC_CLASS_$_NSMutableParagraphStyle", referenced from:
      objc-class-ref in BaiduMapAPI_Base(VBGL.o)
  "_UIGraphicsPushContext", referenced from:
      _baidu_vi::vi_map::GenTextImage(unsigned short*, unsigned int, unsigned int, unsigned int&, unsigned int&, unsigned int&, unsigned int&, unsigned long, unsigned long, unsigned long, unsigned int, int, _baidu_vi::vi_map::TextAlignedType) in BaiduMapAPI_Base(VBGL.o)
  "_NSForegroundColorAttributeName", referenced from:
      _baidu_vi::vi_map::GenTextImage(unsigned short*, unsigned int, unsigned int, unsigned int&, unsigned int&, unsigned int&, unsigned int&, unsigned long, unsigned long, unsigned long, unsigned int, int, _baidu_vi::vi_map::TextAlignedType) in BaiduMapAPI_Base(VBGL.o)
  "_NSStrokeColorAttributeName", referenced from:
      _baidu_vi::vi_map::GenTextImage(unsigned short*, unsigned int, unsigned int, unsigned int&, unsigned int&, unsigned int&, unsigned int&, unsigned long, unsigned long, unsigned long, unsigned int, int, _baidu_vi::vi_map::TextAlignedType) in BaiduMapAPI_Base(VBGL.o)
  "_NSStrokeWidthAttributeName", referenced from:
      _baidu_vi::vi_map::GenTextImage(unsigned short*, unsigned int, unsigned int, unsigned int&, unsigned int&, unsigned int&, unsigned int&, unsigned long, unsigned long, unsigned long, unsigned int, int, _baidu_vi::vi_map::TextAlignedType) in BaiduMapAPI_Base(VBGL.o)
  "_OBJC_CLASS_$_UIButton", referenced from:
      objc-class-ref in BaiduMapAPI_Map(BMKActionPaopaoView.o)
      objc-class-ref in BaiduMapAPI_Base(StretchImageUtil.o)
      objc-class-ref in BaiduMapAPI_Base(BMLogService.o)
  "_OBJC_CLASS_$_UITapGestureRecognizer", referenced from:
      objc-class-ref in BaiduMapAPI_Map(BMKAnnotationView.o)
  "_UIGraphicsBeginImageContextWithOptions", referenced from:
      -[BMKMapView takeSnapshot:] in BaiduMapAPI_Map(BMKMapView.o)
  "_UIGraphicsGetImageFromCurrentImageContext", referenced from:
      -[BMKMapView takeSnapshot:] in BaiduMapAPI_Map(BMKMapView.o)
      _baidu_vi::SaveBufferBmp2Png(char*, int, int, int, _baidu_vi::CVString&) in BaiduMapAPI_Base(VOSPng.o)
  "_UIApplicationWillResignActiveNotification", referenced from:
      -[BMKMapView registerNotification] in BaiduMapAPI_Map(BMKMapView.o)
      -[BMKMapView unRegisterNotification] in BaiduMapAPI_Map(BMKMapView.o)
  "_UIGraphicsBeginImageContext", referenced from:
      _baidu_vi::SaveBufferBmp2Png(char*, int, int, int, _baidu_vi::CVString&) in BaiduMapAPI_Base(VOSPng.o)
  "_UIGraphicsPopContext", referenced from:
      _baidu_vi::vi_map::GenTextImage(unsigned short*, unsigned int, unsigned int, unsigned int&, unsigned int&, unsigned int&, unsigned int&, unsigned long, unsigned long, unsigned long, unsigned int, int, _baidu_vi::vi_map::TextAlignedType) in BaiduMapAPI_Base(VBGL.o)
  "_OBJC_METACLASS_$_UIControl", referenced from:
      _OBJC_METACLASS_$_PaopaoButton in BaiduMapAPI_Map(PaopaoBaseView.o)
  "_UIEdgeInsetsZero", referenced from:
      -[BMKMapView initSubView] in BaiduMapAPI_Map(BMKMapView.o)
  "_OBJC_METACLASS_$_UIView", referenced from:
      _OBJC_METACLASS_$_BaseMapScaleView in BaiduMapAPI_Map(BaseMapScaleView.o)
      _OBJC_METACLASS_$_BMKOverlayView in BaiduMapAPI_Map(BMKOverlayView.o)
      _OBJC_METACLASS_$_CompassView in BaiduMapAPI_Map(CompassView.o)
      _OBJC_METACLASS_$__BMK_BaiduMap_EAGLView in BaiduMapAPI_Map(EAGLView.o)
      _OBJC_METACLASS_$_BMKTapDetectingView in BaiduMapAPI_Map(BMKTapDetectingView.o)
      _OBJC_METACLASS_$_BMKInternalMapView in BaiduMapAPI_Map(MapView.o)
      _OBJC_METACLASS_$_BMKMapView in BaiduMapAPI_Map(BMKMapView.o)
      ...
  "_UIDeviceOrientationDidChangeNotification", referenced from:
      -[BMKMapView registerNotification] in BaiduMapAPI_Map(BMKMapView.o)
      -[BMKMapView unRegisterNotification] in BaiduMapAPI_Map(BMKMapView.o)
  "_OBJC_CLASS_$_UILongPressGestureRecognizer", referenced from:
      objc-class-ref in BaiduMapAPI_Map(BMKTapDetectingView.o)
      objc-class-ref in BaiduMapAPI_Map(BMKAnnotationView.o)
  "_NSParagraphStyleAttributeName", referenced from:
      _baidu_vi::vi_map::GenTextImage(unsigned short*, unsigned int, unsigned int, unsigned int&, unsigned int&, unsigned int&, unsigned int&, unsigned long, unsigned long, unsigned long, unsigned int, int, _baidu_vi::vi_map::TextAlignedType) in BaiduMapAPI_Base(VBGL.o)
  "_OBJC_CLASS_$_UIApplication", referenced from:
      objc-class-ref in BaiduMapAPI_Map(MapView.o)
      objc-class-ref in BaiduMapAPI_Base(BMLogService.o)
      objc-class-ref in BaiduMapAPI_Base(VDeviceAPI.o)
  "_OBJC_CLASS_$_UIScreen", referenced from:
      objc-class-ref in BaiduMapAPI_Map(EAGLView.o)
      objc-class-ref in BaiduMapAPI_Map(BMMapViewManager.o)
      objc-class-ref in BaiduMapAPI_Map(HardwareInfo.o)
      objc-class-ref in BaiduMapAPI_Search(BMKBaseURLRequestSerialization.o)
      objc-class-ref in BaiduMapAPI_Search(BMKBaseURLResponseSerialization.o)
      objc-class-ref in BaiduMapAPI_Base(BMSDKDeviceInfo.o)
      objc-class-ref in BaiduMapAPI_Base(UIDeviceScreen.o)
      ...
  "_OBJC_CLASS_$_UIView", referenced from:
      _OBJC_CLASS_$_BaseMapScaleView in BaiduMapAPI_Map(BaseMapScaleView.o)
      _OBJC_CLASS_$_BMKOverlayView in BaiduMapAPI_Map(BMKOverlayView.o)
      _OBJC_CLASS_$_CompassView in BaiduMapAPI_Map(CompassView.o)
      objc-class-ref in BaiduMapAPI_Map(CompassView.o)
      _OBJC_CLASS_$__BMK_BaiduMap_EAGLView in BaiduMapAPI_Map(EAGLView.o)
      _OBJC_CLASS_$_BMKTapDetectingView in BaiduMapAPI_Map(BMKTapDetectingView.o)
      objc-class-ref in BaiduMapAPI_Map(MapView.o)
      ...
  "_OBJC_CLASS_$_UIControl", referenced from:
      _OBJC_CLASS_$_PaopaoButton in BaiduMapAPI_Map(PaopaoBaseView.o)
  "_OBJC_CLASS_$_UITextView", referenced from:
      objc-class-ref in BaiduMapAPI_Base(BMLogService.o)
  "_OBJC_CLASS_$_UILabel", referenced from:
      objc-class-ref in BaiduMapAPI_Map(PaopaoBaseView.o)
  "_UIApplicationDidBecomeActiveNotification", referenced from:
      -[BMKMapView registerNotification] in BaiduMapAPI_Map(BMKMapView.o)
      -[BMKMapView unRegisterNotification] in BaiduMapAPI_Map(BMKMapView.o)
  "_OBJC_CLASS_$_UIImage", referenced from:
      objc-class-ref in BaiduMapAPI_Map(BMKOverlayView.o)
      objc-class-ref in BaiduMapAPI_Map(BMKPinAnnotationView.o)
      objc-class-ref in BaiduMapAPI_Map(CompassView.o)
      objc-class-ref in BaiduMapAPI_Map(BMKMapView.o)
      objc-class-ref in BaiduMapAPI_Map(LocationView.o)
      objc-class-ref in BaiduMapAPI_Search(BMKBaseURLResponseSerialization.o)
      l_OBJC_$_CATEGORY_UIImage_$_BMKBaseNetworkingSafeImageLoading in BaiduMapAPI_Search(BMKBaseURLResponseSerialization.o)
      ...
  "_UIApplicationMain", referenced from:
      _main in main.o
  "_OBJC_CLASS_$_UIDevice", referenced from:
      objc-class-ref in BaiduMapAPI_Map(LocalMapImport.o)
      objc-class-ref in BaiduMapAPI_Map(LocalMap.o)
      objc-class-ref in BaiduMapAPI_Map(BMKAnnotationView.o)
      objc-class-ref in BaiduMapAPI_Search(BMKBaseURLRequestSerialization.o)
      objc-class-ref in BaiduMapAPI_Base(BMSDKDeviceInfo.o)
      objc-class-ref in BaiduMapAPI_Base(UIDeviceScreen.o)
      objc-class-ref in BaiduMapAPI_Base(VBGL.o)
      ...
     (maybe you meant: _OBJC_CLASS_$_UIDeviceScreen)
  "_OBJC_CLASS_$_UIFont", referenced from:
      objc-class-ref in BaiduMapAPI_Map(BaseMapScaleView.o)
      objc-class-ref in BaiduMapAPI_Map(PaopaoBaseView.o)
      objc-class-ref in BaiduMapAPI_Base(VBGL.o)
      objc-class-ref in BaiduMapAPI_Base(BMLogService.o)
  "_OBJC_CLASS_$_UIViewController", referenced from:
      _OBJC_CLASS_$_ViewController in ViewController.o
  "_NSFontAttributeName", referenced from:
      +[BMKVIDrawTextHelper sizeWithFont:strings:] in BaiduMapAPI_Base(VBGL.o)
      _baidu_vi::vi_map::GenTextImage(unsigned short*, unsigned int, unsigned int, unsigned int&, unsigned int&, unsigned int&, unsigned int&, unsigned long, unsigned long, unsigned long, unsigned int, int, _baidu_vi::vi_map::TextAlignedType) in BaiduMapAPI_Base(VBGL.o)
      _baidu_vi::vi_map::GetFontTextrueSizeOS(unsigned short*, unsigned int, unsigned int, unsigned short*) in BaiduMapAPI_Base(VBGL.o)
      _baidu_vi::vi_map::MetricTextFontSizeOS(unsigned short*, int, unsigned int, unsigned int, float&, float&) in BaiduMapAPI_Base(VBGL.o)
  "_OBJC_CLASS_$_UIColor", referenced from:
      objc-class-ref in BaiduMapAPI_Map(BaseMapScaleView.o)
      objc-class-ref in BaiduMapAPI_Map(BMKGradient.o)
      objc-class-ref in BaiduMapAPI_Map(BMKOverlayView.o)
      objc-class-ref in BaiduMapAPI_Map(BMKOverlayGLBasicView.o)
      objc-class-ref in BaiduMapAPI_Map(PaopaoBaseView.o)
      objc-class-ref in BaiduMapAPI_Map(MapView.o)
      objc-class-ref in BaiduMapAPI_Map(BMKGradient+Interval.o)
      ...
  "_OBJC_CLASS_$_UIImageView", referenced from:
      objc-class-ref in BaiduMapAPI_Map(CompassView.o)
      objc-class-ref in BaiduMapAPI_Map(BMKMapView.o)
      objc-class-ref in BaiduMapAPI_Base(StretchImageUtil.o)
  "_UIImagePNGRepresentation", referenced from:
      _baidu_vi::vi_map::WriteBitmapToFile(void*, int, int, int) in BaiduMapAPI_Base(VBGL.o)
      _baidu_vi::SaveBufferBmp2Png(char*, int, int, int, _baidu_vi::CVString&) in BaiduMapAPI_Base(VOSPng.o)
  "_UIGraphicsGetCurrentContext", referenced from:
      -[BaseMapScaleView drawRect:] in BaiduMapAPI_Map(BaseMapScaleView.o)
      -[BMKOverlayView drawRect:] in BaiduMapAPI_Map(BMKOverlayView.o)
      -[BaiduMapEAGLView drawRect:] in BaiduMapAPI_Map(EAGLView.o)
      -[BMKMapView takeSnapshot:] in BaiduMapAPI_Map(BMKMapView.o)
      -[SingleCircleView drawRect:] in BaiduMapAPI_Map(LocationView.o)
      _baidu_vi::SaveBufferBmp2Png(char*, int, int, int, _baidu_vi::CVString&) in BaiduMapAPI_Base(VOSPng.o)
  "_NSBackgroundColorAttributeName", referenced from:
      _baidu_vi::vi_map::GenTextImage(unsigned short*, unsigned int, unsigned int, unsigned int&, unsigned int&, unsigned int&, unsigned int&, unsigned long, unsigned long, unsigned long, unsigned int, int, _baidu_vi::vi_map::TextAlignedType) in BaiduMapAPI_Base(VBGL.o)
  "_OBJC_CLASS_$_UIResponder", referenced from:
      _OBJC_CLASS_$_AppDelegate in AppDelegate.o
  "_OBJC_METACLASS_$_UIResponder", referenced from:
      _OBJC_METACLASS_$_AppDelegate in AppDelegate.o
  "_UIGraphicsEndImageContext", referenced from:
      -[BMKMapView takeSnapshot:] in BaiduMapAPI_Map(BMKMapView.o)
      _baidu_vi::SaveBufferBmp2Png(char*, int, int, int, _baidu_vi::CVString&) in BaiduMapAPI_Base(VOSPng.o)
  "_OBJC_METACLASS_$_UIViewController", referenced from:
      _OBJC_METACLASS_$_ViewController in ViewController.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

从网上查询得知，需要将Target->Build Settings->Compile Source AS，从Objective-C++改为Objective-C。

而后，报错信息为：

Undefined symbols for architecture x86_64:
  "_SCNetworkReachabilityGetFlags", referenced from:
      ___52-[BMKBaseNetworkReachabilityManager startMonitoring]_block_invoke.55 in BaiduMapAPI_Search(BMKBaseNetworkReachabilityManager.o)
      -[BMKReachability connectionRequired] in BaiduMapAPI_Base(BMReachability.o)
      -[BMKReachability currentReachabilityStatus] in BaiduMapAPI_Base(BMReachability.o)
  "_SCNetworkReachabilityUnscheduleFromRunLoop", referenced from:
      -[BMKBaseNetworkReachabilityManager stopMonitoring] in BaiduMapAPI_Search(BMKBaseNetworkReachabilityManager.o)
      -[BMKReachability stopNotifer] in BaiduMapAPI_Base(BMReachability.o)
  "_SCNetworkReachabilityScheduleWithRunLoop", referenced from:
      -[BMKBaseNetworkReachabilityManager startMonitoring] in BaiduMapAPI_Search(BMKBaseNetworkReachabilityManager.o)
      -[BMKReachability startNotifer] in BaiduMapAPI_Base(BMReachability.o)
  "_kUTTagClassMIMEType", referenced from:
      -[BMKBaseStreamingMultipartFormData appendPartWithFileURL:name:error:] in BaiduMapAPI_Search(BMKBaseURLRequestSerialization.o)
  "_SCNetworkReachabilityCreateWithName", referenced from:
      +[BMKBaseNetworkReachabilityManager managerForDomain:] in BaiduMapAPI_Search(BMKBaseNetworkReachabilityManager.o)
      +[BMKReachability reachabilityWithHostName:] in BaiduMapAPI_Base(BMReachability.o)
  "_kUTTagClassFilenameExtension", referenced from:
      -[BMKBaseStreamingMultipartFormData appendPartWithFileURL:name:error:] in BaiduMapAPI_Search(BMKBaseURLRequestSerialization.o)
  "_SCNetworkReachabilitySetCallback", referenced from:
      -[BMKBaseNetworkReachabilityManager startMonitoring] in BaiduMapAPI_Search(BMKBaseNetworkReachabilityManager.o)
      -[BMKReachability startNotifer] in BaiduMapAPI_Base(BMReachability.o)
  "_UTTypeCreatePreferredIdentifierForTag", referenced from:
      -[BMKBaseStreamingMultipartFormData appendPartWithFileURL:name:error:] in BaiduMapAPI_Search(BMKBaseURLRequestSerialization.o)
  "_SCNetworkReachabilityCreateWithAddress", referenced from:
      +[BMKBaseNetworkReachabilityManager managerForAddress:] in BaiduMapAPI_Search(BMKBaseNetworkReachabilityManager.o)
      +[BMKReachability reachabilityWithAddress:] in BaiduMapAPI_Base(BMReachability.o)
  "_UTTypeCopyPreferredTagWithClass", referenced from:
      -[BMKBaseStreamingMultipartFormData appendPartWithFileURL:name:error:] in BaiduMapAPI_Search(BMKBaseURLRequestSerialization.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

应该是网络相关的库文件缺失。添加库文件SystemConfiguration.framework之后

还会报错如下：

Undefined symbols for architecture x86_64:
  "_kUTTagClassFilenameExtension", referenced from:
      -[BMKBaseStreamingMultipartFormData appendPartWithFileURL:name:error:] in BaiduMapAPI_Search(BMKBaseURLRequestSerialization.o)
  "_kUTTagClassMIMEType", referenced from:
      -[BMKBaseStreamingMultipartFormData appendPartWithFileURL:name:error:] in BaiduMapAPI_Search(BMKBaseURLRequestSerialization.o)
  "_UTTypeCreatePreferredIdentifierForTag", referenced from:
      -[BMKBaseStreamingMultipartFormData appendPartWithFileURL:name:error:] in BaiduMapAPI_Search(BMKBaseURLRequestSerialization.o)
  "_UTTypeCopyPreferredTagWithClass", referenced from:
      -[BMKBaseStreamingMultipartFormData appendPartWithFileURL:name:error:] in BaiduMapAPI_Search(BMKBaseURLRequestSerialization.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

再添加库文件 MobileCoreServices.framework能够编译成功。

大部分Undefined symbols for architecture x86_64都是缺失库文件导致的，可以根据报错信息确定缺失的库文件，添加到工程。