I have converted the Native framework Redpark Serial SDK 1.0.5 into Binding Library (named: RedparkBinding) and using it in one of my project.
I followed each steps carefully in Walkthrough: Binding an iOS Objective-C Library
RedparkBinding project's build result is succeeded.
However, I am facing a strange issue. App is crashing on launch (Reason: NullReferenceException - Inside the sdk there is singleton class which is getting always null).

Few More Details:
- This happens in DEBUG as well as RELEASE mode.
- Supported architecture is ARM64
- Linker Behaviour : Link Framework SDKs Only
- Native SDK sample runs perfectly.
I know that the library itself is working as expected, because it is also used in a native iOS application. I'm just trying to figure out what I'm missing in my Binding project configuration.
Here is the source .h file associated with my .a library:
#import <Foundation/Foundation.h>
NS_ASSUME_NONNULL_BEGIN
// DEFAULT VALUES
// baudRate == 9600
// dataConfiguration == kDataConfig_8N1
// enableRtsCtsFlowControl == NO
// enableDtrDsrFlowControl == NO
// enableSoftwareFlowControl == NO
// dtr == FALSE
// rts == FALSE
enum SerialPortDataConfiguration
{
kDataConfig_8N1, // 8bit, no parity, one stop bit
kDataConfig_8O1, // 8bit, odd parity, one stop bit
kDataConfig_8E1, // 8bit, even parity, one stop bit
kDataConfig_7O1, // 7bit, odd parity, one stop bit
kDataConfig_7E1, // 7bit, even parity, one stop bit
kDataConfig_8N2, // 8bit, no parity, two stop bits
kDataConfig_8O2, // 8bit, odd parity, two stop bits
kDataConfig_8E2, // 8bit, even parity, two stop bits
};
@class RedSerialPort;
@protocol RedSerialPortDelegate <NSObject>
@optional
// called when serial port's transmit FIFO is empty
-(void) transmitFifoIsEmpty:(RedSerialPort *)thePort;
// called when any of the rx modem signals change state (CTS, DSR, DCD or RI)
// user can check value of each modem signal property to determine current state
// optionally, user can set an observer for the modem signal property interested in
- (void) modemSignalChange:(RedSerialPort *)thePort;
// called when TX or RX Flow Control state changes
- (void) flowControlStateChange:(RedSerialPort *)thePort flowControlIsHalted:(BOOL)isFlowHalted;
@end
@interface RedSerialPort : NSObject
{
}
@property (nonatomic, weak) id <RedSerialPortDelegate> delegate;
@property (readonly) BOOL cts;
@property (readonly) BOOL dsr;
@property (readonly) BOOL dcd;
@property (readonly) BOOL ri;
@property (nonatomic) BOOL dtr;
@property (nonatomic) BOOL rts;
@property (readonly) BOOL isFlowConbtrolHalted;
@property (nonatomic) int baudRate;
@property (nonatomic) enum SerialPortDataConfiguration dataConfiguration;
@property (nonatomic) BOOL enableRtsCtsFlowControl;
@property (nonatomic) BOOL enableDtrDsrFlowControl;
@property (nonatomic) BOOL enableSoftwareFlowControl;
// send NSData bytes over serial connection
// calls sendCompleteBlock when all bytes in the NSData are transferred from UART FIFO
-(BOOL)sendData:(NSData *)data sendDataComplete:(void (^)(void))sendCompleteBlock;
// post a read to the serial port
// recvCompleBlock is called when bytes are received
-(BOOL)recvData:(void (^)(NSData *))recvCompleteBlock;
/* =============================================================*/
enum
{
kFwUpdataComplete = 0,
kFwUpdataInProgress = 1,
kFwUpdataErasingSectors = 2,
kFwUpdataRebootingDevice = 3,
kFwUpdataBadAddress = 0x81,
kFwUpdataVerifyFailed = 0x82,
kFwUpdataWriteError = 0x83,
kFwUpdataBadLength = 0x84,
kFwUpdataFlashTimeout = 0x85
};
// Check if connected serial device has latest firmware
-(BOOL)isFirmwareCurrent;
// update serial device firmware to latest version
// updateProgressBlock will be called with firmare download progress
// progress is a value 0-100 indicating the percent of file downloaded.
// state = kFwUpdataInProgress - download is in progress.
// state = kFwUpdataComplete - download is complete and was successful
// state = kFwUpdataRebootingDevice - normal expected state during update
// state = kFwUpdataErasingSectors - normal expected state during update
// state = 0x8n - an error occurred during download and was stopped. Cable was not updated.
-(void)updateFirmware:(void (^)(int progress, uint8_t state))updateProgressBlock;
@end
@protocol RedSerialDeviceManagerDelegate <NSObject>
//
// called when a device is discovered
//
- (void) deviceDetected:(RedSerialPort *)thePort;
//
// called when device connection is broken, object is now orphaned
//
- (void) deviceDisconnected:(RedSerialPort *)thePort;
@end
@interface RedSerialDeviceManager : NSObject
{
}
@property (nonatomic, weak) id <RedSerialDeviceManagerDelegate> delegate;
// return singleton RedSerialDeviceManager
+ (RedSerialDeviceManager *)sharedManager;
// Call to enumerate connected device or register for notifications
// app should call this once at app launch
- (void) startDiscovery;
// application must call this when re-entering foreground to resume communication
// session with accessory
-(void) resume;
// called to clean up existing communication sessions with device
// app must call when going into background
- (void) stop;
@end
NS_ASSUME_NONNULL_END
And here is the C# associated interface created with sharpie
using System;
using Foundation;
using ObjCRuntime;
namespace RedparkLibrary
{
// @protocol RedSerialPortDelegate <NSObject>
[Protocol, Model(AutoGeneratedName = true)]
[BaseType(typeof(NSObject))]
interface RedSerialPortDelegate
{
// @optional -(void)transmitFifoIsEmpty:(RedSerialPort * _Nonnull)thePort;
[Export("transmitFifoIsEmpty:")]
void TransmitFifoIsEmpty(RedSerialPort thePort);
// @optional -(void)modemSignalChange:(RedSerialPort * _Nonnull)thePort;
[Export("modemSignalChange:")]
void ModemSignalChange(RedSerialPort thePort);
// @optional -(void)flowControlStateChange:(RedSerialPort * _Nonnull)thePort flowControlIsHalted:(BOOL)isFlowHalted;
[Export("flowControlStateChange:flowControlIsHalted:")]
void FlowControlStateChange(RedSerialPort thePort, bool isFlowHalted);
}
// @interface RedSerialPort : NSObject
[BaseType(typeof(NSObject))]
interface RedSerialPort
{
[Wrap("WeakDelegate")]
[NullAllowed]
RedSerialPortDelegate Delegate { get; set; }
// @property (nonatomic, weak) id<RedSerialPortDelegate> _Nullable delegate;
[NullAllowed, Export("delegate", ArgumentSemantic.Weak)]
NSObject WeakDelegate { get; set; }
// @property (readonly) BOOL cts;
[Export("cts")]
bool Cts { get; }
// @property (readonly) BOOL dsr;
[Export("dsr")]
bool Dsr { get; }
// @property (readonly) BOOL dcd;
[Export("dcd")]
bool Dcd { get; }
// @property (readonly) BOOL ri;
[Export("ri")]
bool Ri { get; }
// @property (nonatomic) BOOL dtr;
[Export("dtr")]
bool Dtr { get; set; }
// @property (nonatomic) BOOL rts;
[Export("rts")]
bool Rts { get; set; }
// @property (readonly) BOOL isFlowConbtrolHalted;
[Export("isFlowConbtrolHalted")]
bool IsFlowConbtrolHalted { get; }
// @property (nonatomic) int baudRate;
[Export("baudRate")]
int BaudRate { get; set; }
// @property (nonatomic) enum SerialPortDataConfiguration dataConfiguration;
[Export("dataConfiguration", ArgumentSemantic.Assign)]
SerialPortDataConfiguration DataConfiguration { get; set; }
// @property (nonatomic) BOOL enableRtsCtsFlowControl;
[Export("enableRtsCtsFlowControl")]
bool EnableRtsCtsFlowControl { get; set; }
// @property (nonatomic) BOOL enableDtrDsrFlowControl;
[Export("enableDtrDsrFlowControl")]
bool EnableDtrDsrFlowControl { get; set; }
// @property (nonatomic) BOOL enableSoftwareFlowControl;
[Export("enableSoftwareFlowControl")]
bool EnableSoftwareFlowControl { get; set; }
// -(BOOL)sendData:(NSData * _Nonnull)data sendDataComplete:(void (^ _Nonnull)(void))sendCompleteBlock;
[Export("sendData:sendDataComplete:")]
bool SendData(NSData data, Action sendCompleteBlock);
// -(BOOL)recvData:(void (^ _Nonnull)(NSData * _Nonnull))recvCompleteBlock;
[Export("recvData:")]
bool RecvData(Action<NSData> recvCompleteBlock);
// -(BOOL)isFirmwareCurrent;
[Export("isFirmwareCurrent")]
bool IsFirmwareCurrent { get; }
// -(void)updateFirmware:(void (^ _Nonnull)(int, uint8_t))updateProgressBlock;
[Export("updateFirmware:")]
void UpdateFirmware(Action<int, byte> updateProgressBlock);
}
// @protocol RedSerialDeviceManagerDelegate <NSObject>
[Protocol, Model(AutoGeneratedName = true)]
[BaseType(typeof(NSObject))]
interface RedSerialDeviceManagerDelegate
{
// @required -(void)deviceDetected:(RedSerialPort * _Nonnull)thePort;
[Abstract]
[Export("deviceDetected:")]
void DeviceDetected(RedSerialPort thePort);
// @required -(void)deviceDisconnected:(RedSerialPort * _Nonnull)thePort;
[Abstract]
[Export("deviceDisconnected:")]
void DeviceDisconnected(RedSerialPort thePort);
}
// @interface RedSerialDeviceManager : NSObject
[BaseType(typeof(NSObject))]
interface RedSerialDeviceManager
{
[Wrap("WeakDelegate")]
[NullAllowed]
RedSerialDeviceManagerDelegate Delegate { get; set; }
// @property (nonatomic, weak) id<RedSerialDeviceManagerDelegate> _Nullable delegate;
[NullAllowed, Export("delegate", ArgumentSemantic.Weak)]
NSObject WeakDelegate { get; set; }
// +(RedSerialDeviceManager * _Nonnull)sharedManager;
[Static]
[Export("sharedManager")]
RedSerialDeviceManager SharedManager { get; }
// -(void)startDiscovery;
[Export("startDiscovery")]
void StartDiscovery();
// -(void)resume;
[Export("resume")]
void Resume();
// -(void)stop;
[Export("stop")]
void Stop();
}
// @interface RedparkBinding : NSObject
[BaseType(typeof(NSObject))]
interface RedparkBinding
{
}
}
Here is the LinkWith options for .a file [assembly: LinkWith("libRedparkBinding.a”, SmartLink = true, ForceLoad = true)]
And Makefile file:
XBUILD=/Applications/Xcode.app/Contents/Developer/usr/bin/xcodebuild
PROJECT_ROOT=./RedparkBinding
PROJECT=$(PROJECT_ROOT)/RedparkBinding.xcodeproj
TARGET=RedparkBinding
all: lib$(TARGET).a
lib$(TARGET)-arm64.a:
$(XBUILD) -project $(PROJECT) -target $(TARGET) -sdk iphoneos -arch arm64 -configuration Release clean build
-mv $(PROJECT_ROOT)/build/Release-iphoneos/lib$(TARGET).a $@
lib$(TARGET).a: lib$(TARGET)-arm64.a
xcrun -sdk iphoneos lipo -create -output $@ $^
clean:
-rm -f .a .dll
Also I’m attaching all required files (native library framework, native library sample code, binding code, SDK user guide) here.
I appreciate any suggestions from the community.