Unable to write using CFWriteStream

Question

I have created a UDP CFSocket and I'm able to send data without using any file handles. But, when I create CFReadStreamRef, CFWriteStreamRef and use them to send data, it fails. The control does not return. Can anyone help me regarding this? The code is as below:

-(void) CFSocketType2
{


CFSocketRef s = CFSocketCreate(kCFAllocatorDefault, PF_INET,
                               SOCK_DGRAM , IPPROTO_UDP,
                               0,
                               NULL,
                               NULL);

struct sockaddr_in      sin;
struct hostent           *host;

host = gethostbyname("localhost");
memset(&sin, 0, sizeof(sin));
memcpy(&(sin.sin_addr), host->h_addr,host->h_length);
sin.sin_family = AF_INET;
sin.sin_port = htons(5527);

CFDataRef address, data;

UInt8 message[] = "Hello world 123";
address = CFDataCreate(NULL, (UInt8 *)&sin, sizeof(sin));
data = CFDataCreate(NULL, message, sizeof(message));

//Sending data without using file handles
CFSocketConnectToAddress(s, address, 0);
CFSocketSendData(s, NULL, data, 0);


// The problem starts here
CFReadStreamRef readStream = NULL;
CFWriteStreamRef writeStream = NULL;


CFStreamCreatePairWithSocket(kCFAllocatorDefault, CFSocketGetNative(s), &readStream, &writeStream);


if (readStream && writeStream)
{
    CFReadStreamSetProperty(readStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
    CFWriteStreamSetProperty(writeStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
    if (! CFReadStreamOpen(readStream) || ! CFWriteStreamOpen(writeStream))
    {
        NSLog(@"Could not initialize streams!");
    }
    else
    {
        UInt8 msg [] ="Hello World";
        CFIndex a =  CFWriteStreamWrite(writeStream, msg, sizeof(msg));
        NSLog(@"Return value is %d", a);
    }
}
}

Answer 1

I was working on a UDP socket some time back. The problem in your code is that you are not connecting the server before you can use the the socket.

The code which I wrote some time back is below. Hope it helps

-(void) BSDSocketType
{
int sockfd;
struct sockaddr_in servaddr;
char sendline[] = "hello world";

char addr[] = "127.0.0.1";


sockfd=socket(AF_INET,SOCK_DGRAM,0);
bzero(&servaddr,sizeof(servaddr));
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr=inet_addr(addr);
servaddr.sin_port=htons(5527);



// All these are foundation classes
CFReadStreamRef readStraem = NULL;
CFWriteStreamRef writeStream = NULL;


int status =0;
// Create CFSocket
status = -3;
status = fcntl(sockfd, F_SETFL, O_NONBLOCK);
if (status == -1)
{
    NSLog(@"Not able to create Non blocking socket");
}
int reuseaddr = 1;
status = setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &reuseaddr, sizeof(reuseaddr));
if (status == -1)
{
    NSLog(@"Error 2");
}
int nosigpipe = 1;
status = setsockopt(sockfd, SOL_SOCKET, SO_NOSIGPIPE, &nosigpipe, sizeof(nosigpipe));
if (status == -1)
{
    NSLog(@"Error");
}

CFStreamCreatePairWithSocket(NULL, (CFSocketNativeHandle)sockfd, &readStraem, &writeStream);
if (!readStraem || !writeStream)
{
    NSLog(@"Error");
}
NSLog(@"OK");


int n = connect(sockfd, (struct sockaddr *)&servaddr,sizeof(servaddr));
if ( n < 0)
{
    printf("Connect error with port %s\n", strerror(errno));
}


CFReadStreamSetProperty(readStraem, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanFalse);
CFWriteStreamSetProperty(writeStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanFalse);

CFReadStreamOpen(readStraem);
CFWriteStreamOpen(writeStream);

NSLog(@"%ld",CFWriteStreamGetStatus(writeStream));
NSLog(@"%ld",CFReadStreamGetStatus(readStraem));

if(CFWriteStreamCanAcceptBytes(writeStream))
{
    NSLog(@"Ok");
    UInt8 msg [] ="CF STReamHello World from cftype 2";
    CFIndex a =  CFWriteStreamWrite(writeStream, msg, sizeof(msg));
    NSLog(@"%ld",a);
}
else
    NSLog(@"Cannot accept bytes");
NSLog(@"Ok");

NSInputStream * inputStream = (__bridge NSInputStream *)(readStraem);
NSOutputStream * outputStream = (__bridge NSOutputStream *)(writeStream);

[inputStream open];
[outputStream open];

UInt8 msg [] ="NSStream Hello World from cftype 2";
int a;
if ([outputStream hasSpaceAvailable])
{
    a = [outputStream write:msg maxLength:sizeof(msg)];
            NSLog(@"Ok");
}
NSLog(@"%d",a);

}