Example CFStream send

networkexample

 
 -(void) networkExample
 {
 
    uint8_t buf[5];
    buf[0]=0xe0;
    buf[1]=0x4f;
    buf[2]=0xd0;
    buf[3]=0x20;
    buf[4]=0xea;
  
     NSLog(@"Data=%@ %lu",sendData,sizeof(buf));
    
    CFReadStreamRef readStream;
    CFWriteStreamRef writeStream;
    CFStreamCreatePairWithSocketToHost(NULL, (CFStringRef)@"127.0.0.1", 1234, &readStream, &writeStream);
    
    self.inputStream = (__bridge_transfer NSInputStream *)readStream;
    self.outputStream = (__bridge_transfer NSOutputStream *)writeStream;
    [self.inputStream setDelegate:self];
    [self.outputStream setDelegate:self];
    [self.inputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    [self.outputStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    [self.inputStream open];
    [self.outputStream open];
    [self.outputStream write:buf maxLength:sizeof(buf)];
    
}

- (void)stream:(NSStream *)theStream handleEvent:(NSStreamEvent)streamEvent
{
    NSLog(@"received event %lu on %@",streamEvent,theStream);
}

Test against nc -l 1234 command in a terminal

Xcode console log -

2014-05-15 17:50:56.426 CocoaTest[20567:303] Data= 5
2014-05-15 17:50:56.436 CocoaTest[20567:303] received event 1 on <__NSCFOutputStream: 0x608000092890>
2014-05-15 17:50:56.436 CocoaTest[20567:303] received event 4 on <__NSCFOutputStream: 0x608000092890>
2014-05-15 17:50:56.438 CocoaTest[20567:303] received event 1 on <__NSCFInputStream: 0x608000092840>
2014-05-15 17:50:56.438 CocoaTest[20567:303] received event 4 on <__NSCFOutputStream: 0x608000092890>

Terminal output -

$ nc -l 1234 | od -t x1
0000000 e0 4f d0 20 ea
0000005

The Xcode console shows event 1 - stream opened - for both streams and even 4 - space available for the output stream both before and after the write.