Thread stucks in the infinite loop when executed - c

Question

I have developed a chat server program using threads. In this program there are two threads:
One to receive data
One to send data
Both of the threads contain the infinite loop in order to continuously send and receive data. But when it is executed the thread for receiving data gets stuck in the loop.
The code of the server:
{
addr_len=sizeof(cli_addr);
cli_sock=accept(sock,(struct sockaddr *)&cli_addr,&addr_len);
if(cli_sock<0)
printf("\nConnetion Error\n");
else
printf("conneted\n");
status_s=pthread_create(&thread_s,NULL,send_data,&cli_sock);
if(status_s==0)
printf("sending");
status_r=pthread_create(&thread_r,NULL,recieve_data,&cli_sock);
if(status_r==0)
printf("recieving");
}
}
void *recieve_data(void *num)
{
int *sock_r=(int *) num;
int sock=*sock_r;
char msg[50];
while(1)
{
recv(sock_r,msg,sizeof(msg),0);
if(strcmp(msg,"exit")==0)
{
break;
}
printf("recieved data:");
recv(sock_r,msg,sizeof(msg),0);
printf("\n%s",msg);
}
}
void *send_data(void *num)
{
int *sock_s=(int *) num;
int sock=*sock_s;
char msg[50];
while(1)
{
gets(msg);
//printf("sending data");
if(strcmp(msg,"exit")==0)
{
break;
}
send(sock_s,msg,sizeof(msg),0);
}
send(sock,msg,sizeof(msg),0);
}

Answer 1

Would be better if control commands like "exit" are int based.
Also, receive data doesn't handle peer connection closure status. Ex:
Copied from here.
// Receive until the peer closes the connection
do {
iResult = recv(ConnectSocket, recvbuf, recvbuflen, 0);
if ( iResult > 0 )
printf("Bytes received: %d\n", iResult);
else if ( iResult == 0 )
printf("Connection closed\n");
else
printf("recv failed: %d\n", WSAGetLastError());
} while( iResult > 0 );