Terminating secondary thread from another thread
Hi everyone, I'm new to this forum. If my qurestion is in wrong place please correct me.
I'm currently learning about the multithread, and TCP socket. But I was wondering why my code have problem. I search over google still cant fix my problem. Hope anyone can direct me into the right. Thanks
Basically, this is a TCP client program which do simple msg tranfsfer. When the connection establish, the thread "new_thr" will create another 2 thread which are "send_thr" and "recv_thr". One is to send message to server and another one is to receive message from server. At final, what I want is when either receive or user input an "Q" or "q", the whole process will terminated. So currently I m trying to use thread_cancel to terminate another thread.
Here is my code
PHP Code:
[CODE]/* threadclient.c */
#include <pthread.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
void *cthr_do();
void *cthr_send();
void *cthr_recv();
int main()
{
int k;
pthread_t new_thr;
int check = pthread_create(&new_thr, NULL, cthr_do, NULL );
if(check!=0)
printf("The thread cannot be created!");
pthread_join (new_thr, NULL);
printf("The whole process terminated\n");
return 0;
}
void *cthr_do()
{
printf("thread run sucessful\n");
int sock, bytes_received, connected, s, r;
char send_data[1024],recv_data[1024];
struct hostent *host;
struct sockaddr_in6 server_addr;
host = gethostbyname("::1");
if ((sock = socket(AF_INET6, SOCK_STREAM, 0)) == -1) {
perror("Socket");
exit(1);
}
server_addr.sin6_family = AF_INET6;
server_addr.sin6_port = htons(5000);
server_addr.sin6_addr= in6addr_any/*((struct in_addr *)host->h_addr)*/;
/*bzero(&(server_addr.sin_zero),8);*/
/*memset(&(server_addr.sin_zero),0,8);*/
connected = connect(sock, (struct sockaddr *)&server_addr, sizeof(server_addr));
if (connected== -1)
{
perror("Connect");
exit(1);
}
printf("The connection is established.\n");
pthread_t send_thr, recv_thr;
int chk_send = pthread_create(&send_thr, NULL, cthr_send, (void *)sock);
if(chk_send!=0)
printf("The send message thread cannot be created!");
int chk_recv = pthread_create(&recv_thr, NULL, cthr_recv, (void *)sock);
if(chk_recv!=0)
printf("The receive message thread cannot be created!");
while (1)
{
s = pthread_join (send_thr, NULL);
r = pthread_join (recv_thr, NULL);
if (s && r)
break;
}
close(sock);
printf("closed socket\n");
}
void *cthr_send(void *arg)
{
pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);
char send_data [1024], recv_data[1024];
while (1)
{
printf("\n SEND (q or Q to quit) : ");
gets(send_data)/*,1024,stdin)*/;
if (strcmp(send_data , "q") == 0 || strcmp(send_data , "Q") == 0)
{
send((int) arg, send_data,strlen(send_data), 0);
/*close ((int) arg);*/
break;
}
else
send((int) arg, send_data,strlen(send_data), 0);
}
if ( pthread_cancel(recv_thr) == -1 )
{
perror("pthread_cancel failed");
exit(3);
}
// if (pthread_cancel(recv_thr)!= 0)
// perror ("Thread cancelation "); ;
}
void *cthr_recv(void *arg)
{
pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);
char send_data [1024] , recv_data[1024];
int bytes_received;
while (1)
{
bytes_received = recvfrom((int) arg, recv_data, 1024-1, 0, NULL, NULL);
/*recv((int) arg,recv_data,1024,0);*/
if (bytes_received == -1)
{
/*
* Socket in error state
*/
perror ("Client recv(): ");
exit(1);
}
printf("\nThe number of digit received: %d\n", bytes_received);
recv_data[bytes_received] = '\0';
if (strcmp(recv_data, "q") == 0 || strcmp(recv_data , "Q") == 0)
{
send((int) arg, "q", strlen("q"), 0);
// close((int) arg);
break;
}
else
printf("\n RECEIVED DATA = %s \n" , recv_data);
fflush(stdout);
}
// if (pthread_cancel (send_thr)!= 0)
// perror ("Thread cancelation "); ;
}[/CODE]
When i compile this code with the error shown.
Code:
shufei@shufei-desktop:~/Desktop$ gcc -lpthread threadclient.c -o threadclient
threadclient.c: In function ‘cthr_send’:
threadclient.c:114: error: ‘recv_thr’ undeclared (first use in this function)
threadclient.c:114: error: (Each undeclared identifier is reported only once
threadclient.c:114: error: for each function it appears in.)
is anyone know why it say the recv_thr is undeclare since it was declared in secondary thread. Please forgive my if this is an stupid question.
Regards,
wssoh
