OS X/iOS＆TCP：爲什麼CFSocketSendData在連接重置後調用時會崩潰應用程序？

Question

我用類似這樣的客戶端代碼：

#import <CoreFoundation/CFSocket.h> 
#include <sys/socket.h> 
#include <netinet/in.h> 

void receiveData(CFSocketRef s, 
         CFSocketCallBackType type, 
         CFDataRef address, 
         const void *data, 
         void *info) 
{ 
    CFDataRef df = (CFDataRef) data; 
    int len = CFDataGetLength(df); 
    if(len <= 0) return; 

    CFRange range = CFRangeMake(0,len); 
    UInt8 buffer[len]; 
    NSLog(@"Received %d bytes from socket %d\n", 
        len, CFSocketGetNative(s)); 
    CFDataGetBytes(df, range, buffer); 
    NSLog(@"Client received: %s\n", buffer); 
    NSLog(@"As UInt8 coding: %@", df); 
} 

int main() 
{ 
    CFSocketRef s = CFSocketCreate(NULL, PF_INET, 
              SOCK_STREAM, IPPROTO_TCP, 
              kCFSocketDataCallBack, 
              receiveData, 
              NULL); 
    struct sockaddr_in  sin; 
    struct hostent   *host; 

    host = gethostbyname("********");  
    memset(&sin, 0, sizeof(sin)); 
    memcpy(&(sin.sin_addr), host->h_addr,host->h_length); 
    sin.sin_family = AF_INET; 
    sin.sin_port = htons(888); 

    CFDataRef address, data; 
    UInt8 message[] = "Hello world"; 
    CFRunLoopSourceRef source; 

    address = CFDataCreate(NULL, (UInt8 *)&sin, sizeof(sin)); 
    data = CFDataCreate(NULL, message, sizeof(message)); 

    CFSocketConnectToAddress(s, address, 0); 
    CFSocketSendData(s, NULL, data, 0); 

    CFRelease(address); 
    CFRelease(data); 

    source = CFSocketCreateRunLoopSource(NULL, s, 0); 
    CFRunLoopAddSource(CFRunLoopGetCurrent(), 
         source, 
         kCFRunLoopDefaultMode); 
    CFRelease(source); 
    CFRelease(s); 
    CFRunLoopRun(); 
} 

它發送數據，並得到響應正常。但是TCP不應該只是發送數據，它應該發送數據RELIABLY。

我測試這樣的年表：

1. 客戶端調用CFSocketConnectToAddress
2. 服務器授權客戶端
3. 但是現在服務器應用程序崩潰，並且服務器 - >客戶端發送RST標誌。
4. 之後，客戶撥打CFSocketSendData。

我預計CFSocketSendData返回錯誤或至少拋出異常，但它會導致應用程序崩潰，並且@ try-catch不起作用。

Answer 1

你可以嘗試在第二個參數中使用顯式地址嗎？看看你是否在那之後得到一個錯誤。

CFSocketSendData（s，，data，0）;