Question

我正在尝试将我的iOS应用程序连接到adhoc网络上的打印机，我需要在向打印机发送任何内容之前检查连接是否已打开且有效，我该如何实现？目前我正在做以下事情 CFReadStreamRef readStream; CFWriteStreamRef writeStream;

readStream = NULL;
writeStream = NULL;

CFStreamCreatePairWithSocketToHost(NULL, (__bridge CFStringRef)IPADDRESS, NUM_PORT,NULL ,&writeStream );

if(writeStream)
{
    //inputStream = (__bridge NSInputStream *)readStream;
    oStream = (__bridge NSOutputStream *)writeStream;

    //[iStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    [oStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
    //[iStream setDelegate:delegate];
    [oStream setDelegate:delegate];
    //[iStream open];
    [oStream open];
}

和

   int bytesWritten;
   int bytesTotal = [data length];

   bytesWritten = [oStream write:[data bytes] maxLength: bytesTotal];
   NSLog(@"Bytes Written To Printer : %d",bytesWritten);

但它总是进入并且writeStream永远不会为null所以我无法阻止它尝试将数据推送到套接字。

〜编辑 - 也许我最好解释一下我的问题，我怎么能阻止它挂30秒以上直到它意识到没有连接？

Answer 1

在向打印机发送任何内容之前，我需要检查连接是否已打开且有效，我该如何实现？

通过向打印机发送内容。检测TCP中的连接问题的唯一方法是使用它进行一些I / O.

套接字检查存在TCP / IP连接并缩短超时

1 个答案: