How to keep my main thread and p thread alive? - c

Question

I have a main function which, has a while loop which is Keeping my program live , but when i call the another thread (which is required), my main thread exits or I have to suspend it by calling thread join, i don know if its my codes problem
I have a this function calling my thread
int start_sender_engine(void)
{
thread1_ret = pthread_create(&Send_thread_1, NULL, Sender_thread,(void*) message1);
//pthread_join(Send_thread_1, NULL);
return 0;
}
im calling this thread here ,
now my main thread is like this
int main (int argc, char *argv[])
{
start_sender_engine();
while(1)
{
data.CommandCode=33+cont[0];
data.DataSize=sizeof(cont);
data.Data=cont;
Enqueue_elements(queue_hndl, &data);
usleep(1000*1000);
}
deleteQueue(queue_hndl);
}
my dequeue function is located inside the thread
void *Sender_thread(void *msg_ptr) // Sender Engine
{
char *message;
message = (char *) msg_ptr;
printf("%s\n",message);
fflush(stdout);
/*
* Create a datagram socket on which to send.
*/
sd = socket(AF_INET, SOCK_DGRAM, 0);
if (sd < 0) {
perror("opening datagram socket");
exit(1);
}
/*
* Initialize the group sockaddr structure with a
* group address of 225.1.1.1 and port 5555.
*/
memset((char *) &groupSock, 0, sizeof(groupSock));
groupSock.sin_family = AF_INET;
groupSock.sin_addr.s_addr = inet_addr("225.1.1.2");
groupSock.sin_port = htons(65533);
/*
* Disable loopback so you do not receive your own datagrams.
*/
{
char loopch=0;
if (setsockopt(sd, IPPROTO_IP, IP_MULTICAST_LOOP,
(char *)&loopch, sizeof(loopch)) < 0) {
perror("setting IP_MULTICAST_LOOP:");
close(sd);
exit(1);
}
}
/*
* Set local interface for outbound multicast datagrams.
* The IP address specified must be associated with a local,
* multicast-capable interface.
*/
localInterface.s_addr = inet_addr("192.168.1.10");
if (setsockopt(sd, IPPROTO_IP, IP_MULTICAST_IF,
(char *)&localInterface,
sizeof(localInterface)) < 0) {
perror("setting local interface");
exit(1);
}
/*
* Send a message to the multicast group specified by the
* groupSock sockaddr structure.
*/
//// Queue ////////
queue_hndl = createQueue(1000, (sizeof(SenderData) + 5000) );
while(stop_nw_global!=1)
{
if(no_elements(queue_hndl)>0)
{
temp=Dequeue_elements(queue_hndl);
printf("CMD Code %d",temp->CommandCode);
printf("---Size %d",temp->DataSize);
int *testi = (int*)temp->Data;
printf("Sending- %d\n", testi[0]);
fflush(stdout);
send_packets(*temp,100);
}
else
{
usleep(1000*1000);
printf(".\n");
fflush(stdout);
}
}
return 0;
}
when i comment pthread join, i get a error message as
>>>>>>Sender_Engine_Started<<<<<<<
0 [main] nwudp 1647 cygwin_exception::open_stackdumpfile: Dumping stack trace to
nwudp.exe.stackdump
.
when i un comment pthread join, my thread(Sender_thread)works perfectly, but my while loop inside my main stops
how can i make both alive? or should i create another thread for main?

Answer 1

I have figured out the issue, my queue handle "queue_hndl" was being used in the mains while loop before it was initialized, it was getting initialized just before my thread starts , so i have changed it acquire handle before starting my thread and now it works