how to run the task in parallel? - c

Question

int CreateSocket()
{
// SOCKET connectedSocket;
// SOCKADDR_IN addr;
// char buf[256];
// char buf2[300];
// Winsock starten
HANDLE h1,h2,h3;
double Task2ms_Raster, Task10ms_Raster, Task100ms_Raster ;
long rc;
SOCKET acceptSocket;
rc=startWinsock();
if(rc!=0)
{
printf("Fehler: startWinsock, fehler code: %d\n",rc);
return 1;
}
else
{
printf("Winsock gestartet!\n");
}
// Socket erstellen
acceptSocket=socket(AF_INET,SOCK_STREAM,0);
if(acceptSocket==INVALID_SOCKET)
{
printf("Fehler: Der Socket konnte nicht erstellt werden, fehler code: %d\n",WSAGetLastError());
return 1;
}
else
{
printf("Socket erstellt!\n");
}
memset(&addr,0,sizeof(SOCKADDR_IN));
addr.sin_family=AF_INET;
addr.sin_port=htons(port);
addr.sin_addr.s_addr=htonl(INADDR_ANY);
rc=bind(acceptSocket,(SOCKADDR*)&addr,sizeof(SOCKADDR_IN));
if(rc==SOCKET_ERROR)
{
printf("Fehler: bind, fehler code: %d\n",WSAGetLastError());
return 1;
}
else
{
printf("Socket an port %d gebunden\n",port);
}
rc=listen(acceptSocket,10);
if(rc==SOCKET_ERROR)
{
printf("Fehler: listen, fehler code: %d\n",WSAGetLastError());
return 1;
}
else
{
printf("acceptSocket ist im listen Modus....\n");
}
connectedSocket=accept(acceptSocket,NULL,NULL);
if(connectedSocket==INVALID_SOCKET)
{
printf("Fehler: accept, fehler code: %d\n",WSAGetLastError());
return 1;
}
else
{
printf("Neue Verbindung wurde akzeptiert!\n");
// strcpy(buf,"Hallo wie gehts?");
// rc=send(acceptSocket,buf,9,0);
// Daten austauschen
while(rc!=SOCKET_ERROR)
{
rc=recv(connectedSocket,buf,256,0);
if(rc==0)
{
printf("Server hat die Verbindung getrennt..\n");
break;
}
if(rc==SOCKET_ERROR)
{
printf("Fehler: recv, fehler code: %d\n",WSAGetLastError());
break;
}
XcpIp_RxCallback( (uint16) rc, (uint8*) buf, (uint16) port );
h1=TimerTask(2,TASK1,&Task2ms_Raster);
h2=TimerTask(10,TASK2,&Task10ms_Raster);
h3=TimerTask(100,TASK3,&Task100ms_Raster);
}
}
closesocket(acceptSocket);
closesocket(connectedSocket);
XcpIp_OnTcpCxnClosed((uint16) port );
WSACleanup();
return 0;
}
The above code is a server code and accepts a connection from the client via the ip address and port number. I am accepting the connection and recieving the data from the client. I want to run the TimerTask in the background, timer task is calling a function called TASK1, TASK2 and TASK3 for every 2ms , 10ms and 100ms. So how to run those function in the background. Please someone help me.

Answer 1

If you want to make things run in parallel, you can use threads for Multithreading, or forks for multiprocessing.
Here's an example for multithreading in c:
#include <pthread.h>
void handleClient(SOCKET clientSock)
{
... read and write ...
}
int main()
{
... prepare the server ...
... listen on socket ...
for(;;){
connectedSocket=accept(acceptSocket,NULL,NULL);
pthread_t *tid = malloc( sizeof(pthread_t) );
pthread_create( &tid, NULL, handleClient, connectSocket );
... test, if the server should be killed, and break the loop ...
}
}
Notice, that this is a very minimalistic example. You should also care about "collecting your threads" with pthread_join( tid, NULL );, thus you have to store all your pthread_t-Variables inside an Array or a linked list.