How to create two different processes

[janaki]

hello sir,
i was asked to create two different process where in one process, main function should be there which should have abstract calls as follows:-
port = initialize_port(PORT _TYPE) ;
writeport = (port,buf,size,PORT_TYPE);
readport =(port,buf,size,PORT_TYPE);
closeport();
and in other process qt gui should be there

may i get any suggestion how to do this

please help me this is a bit urgent

thanking u

[Rahul Das]

You can start "here":http://qt-project.org/doc/qt-5.0/qtcore/qprocess.html#details

[janaki]

thank u sir
but i should not use qt related calls for creating the process it should be in C++
can u please guide me
thanking u sir

[Rahul Das]

For that you need platform specific call, imo.

If you are on linux, have a look at "this pdf":http://www.advancedlinuxprogramming.com/alp-folder/alp-ch03-processes.pdf (abt fork, exec etc)

[janaki]

#include<iostream>
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include "structures.h"
#include <string.h>
#include <unistd.h>
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <sys/types.h>
#include <arpa/inet.h>

#include <fcntl.h>
#include <signal.h>

#define MAX_DATA_SIZE 512
#define ID

using namespace std;

struct Message
{
int message_id;
}msg;

void received_data(void);

int main()
{
cout<<"main program"<<endl;

pthread_t thread1,thread2;
int status,status2;

status= pthread_create(&thread1,NULL,received_data,NULL);
status2 = pthread_create(&thread2,NULL,process,NULL);
pthread_join(thread1,NULL);
if(status<0)
{
perror("pthread_create failed");
exit(0);
}

sleep(1);

status = pthread_join(thread1,NULL);

exit (0);
}

void *received_data(void *)
{
std::cerr<<"am in thread"<<std::endl;
Message msg;
printf("Hello\n");
int fd;
sigset_t set;
printf("Hello2\n");
struct sockaddr_in servaddr, cliaddr;

void **status;

fd = socket(AF_INET,SOCK_DGRAM,0);
printf("Hello3\n");

if(fd <0)
cout<<"Socket creation Failed"<<endl;

servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = inet_addr("10.66.48.11"); //server ip addr
// servaddr.sin_addr.s_addr = inet_addr("10.66.48.23"); //server ip addr
servaddr.sin_port = htons(12005); //server poet no.
printf("Hello4\n");
if(bind(fd,(const struct sockaddr *)&servaddr,sizeof(servaddr))<0)
cout<<"BIND FAILED"<<endl;
unsigned char buffer[MAX_DATA_SIZE];

socklen_t len=sizeof(cliaddr);
fcntl(fd,F_SETFL,O_NONBLOCK);

printf("Hello5\n");

for(;;)
{
sleep(3);
int n= recvfrom(fd,buffer,sizeof(buffer),0,(struct sockaddr *)&cliaddr,&len);

            memcpy(&msg,buffer,sizeof(msg));

printf("Hello7\n");
cout<<"Received : bytes"<<n<<" "<<msg.message_id<<endl;

}

pthread_exit(0);

}

i shud have 4 threads in my main program

1. received_data - first threads receive messages
2. process_data - whenever a message is received in first thread a signal should be sent to second thread for processing data - message id received from first thread should be used for processing data
3. health_data - this thread sends health message for every 20 seconds
4. display_data - this thread should display status in the gui.

i have written first thread which is working successfully, but am not getting idea how to send a signal when message is received and how to attach a signal handler when signal is received with the function in the second thread.
kindly suggest me for doing this