Analysis of socket usage and precautions in Android NDK

The entire process of using socket in Android NDK is divided into the following parts:
Part 1: Create a socket and bind the IP address and port
Copy codeThe Code is as follows: # include <sys/select. h>
# Include <sys/socket. h>
# Include <arpa/inet. h>
# Define MAX_DATA_BUF_LEN 10240.
Int sd = INVALID_SOCKET;
Sockaddr_in addr_org; // The sender address.
Sd = socket (AF_INET, SOCK_DGRAM, IPPROTO_UDP); // create a socket
Addr_org.sin_family = AF_INET;
Addr_org.sin_addr.s_addr = inet_addr ("192.128.0.1"); // the IP address of the sender.
Addr_org.sin_port = htons (8080); // sending end Port
Bind (sd, (struct sockaddr *) & (addr_org), sizeof (struct sockaddr_in); // bind the IP address and port

Part 2: send data
Copy codeThe Code is as follows: sockaddr_in addr_dst; // The acceptor address.
Addr_dst.sin_family = AF_INET;
Addr_dst.sin_addr.s_addr = inet_addr ("192.128.0.2"); // acceptor IP Address
Addr_dst.sin_port = htons (8080); // acceptor Port
... // Generate the data to be sent to SendDataBuff. The length is ulLen.
Sendto (sd, SendDataBuff, ulLen, 0, (struct sockaddr *) & (addr_dst), sizeof (sockaddr_in); // send data in SendDataBuff

Part 3: receiving data in a thread (non-blocking)
Copy codeThe Code is as follows: void * SocketReceiveThread (void * pParam)
{
Fd_set fdset;
Struct timeval delayval;
Unsigned long lRetVal;
Delayval. TV _sec = 0;
Delayval. TV _usec = 5000;/* 5 ms latency */
While (! End_flag)
{
FD_ZERO (& fdset );
FD_SET (sd, & fdset );
LRetVal = select (sd + 1, & fdset, NULL, NULL, & delayval); // pay attention to the first parameter.
If (0 = lRetVal)
{
Continue;
}
Else if (SOCKET_ERROR = lRetVal)
{
Break;
}
Else if (FD_ISSET (sd, & fdset )! = 0)
{
Char RecvDataBuff [MAX_DATA_BUF_LEN]; // receives the data buffer.
Unsigned long ulLen = recvfrom (sd, RecvDataBuff, MAX_DATA_BUF_LEN, 0, NULL, NULL );
... // Process received data
}
}
}

Part 4: Disable socket
Close (sd );