Assignments

General Linux programming resources

http://www.linuxjournal.com/article.php?sid=2333

http://www.linuxgazette.com/issue47/bueno.html

http://www-106.ibm.com/developerworks/linux/library/l-rt6/?t=gr,Redhat=Sockets

http://www.linuxjournal.com/article.php?sid=2333

http://pont.net/socket/index.html

http://www.cs.uno.edu/~golden/teach.html

Example

/* client.c */

#include<sys/socket.h>

#include<sys/types.h>

#include<netinet/in.h>

#include<unistd.h>

#include<stdlib.h>

#include<stdio.h>

main(int argc,char *argv[])

   int create_socket;

   int bufsize = 1024;

   char *buffer = malloc(bufsize);

   struct sockaddr_in address;

   if ((create_socket = socket(AF_INET,SOCK_STREAM,0)) > 0)

     printf("The Socket was created\n");

   address.sin_family = AF_INET;

   address.sin_port = htons(15000);

   inet_pton(AF_INET,argv[1],&address.sin_addr);

   if (connect(create_socket,(struct sockaddr *)&address,sizeof(address)) == 0)

     printf("The connection was accepted with the server %s...\n",inet_ntoa(address.sin_addr));

do{

      recv(create_socket,buffer,bufsize,0);

      printf("Message recieved: %s\n",buffer);

      if (strcmp(buffer,"/q")){

         printf("Message to send: ");

         gets(buffer);

         send(cria_socket,buffer,bufsize,0);

   }while (strcmp(buffer,"/q"));

   close(create_socket);

/* server.c */

#include<sys/types.h>

#include<sys/socket.h>

#include<netinet/in.h>

#include<unistd.h>

#include<stdlib.h>

#include<stdio.h>

main()

   int cont,create_socket,new_socket,addrlen;

   int bufsize = 1024;

   char *buffer = malloc(bufsize);

   struct sockaddr_in address;

   printf("\x1B[2J");

   if ((create_socket = socket(AF_INET,SOCK_STREAM,0)) > 0)

     printf("The socket was created\n");

   address.sin_family = AF_INET;

   address.sin_addr.s_addr = INADDR_ANY;

   address.sin_port = htons(15000);

   if (bind(create_socket,(struct sockaddr *)&address,sizeof(address))== 0)

     printf("Binding Socket\n");

   listen(create_socket,3);

   addrlen = sizeof(struct sockaddr_in);

   new_socket = accept(create_socket,(struct sockaddr *)&address,&addrlen);

   if (new_socket > 0){

      printf("The Client %s is connected...\n",inet_ntoa(address.sin_addr));

      for(cont=1;cont<5000;cont++)

        printf("\x7");

do{

      printf("Message to send: ");

      gets(buffer);

      send(new_socket,buffer,bufsize,0);

      recv(new_socket,buffer,bufsize,0);

      printf("Message recieved: %s\n",buffer);

   }while(strcmp(buffer,"/q")); //user ‘q’ to quit

   close(new_socket);

   close(create_socket);

Java

… go to www.javaworld.com and search on threads

Linux C threads: examples for more detail see above in general programming

/***********************************************************************

* Code listing from "Advanced Linux Programming," by CodeSourcery LLC  *

* Copyright (C) 2001 by New Riders Publishing                          *

* See COPYRIGHT for license information.                               *

***********************************************************************/

#include

#include

/* Parameters to print_function.  */

struct char_print_parms

  /* The character to print.  */

  char character;

  /* The number of times to print it.  */

  int count;

};

/* Prints a number of characters to stderr, as given by PARAMETERS,

   which is a pointer to a struct char_print_parms.  */

void* char_print (void* parameters)

  /* Cast the cookie pointer to the right type.  */

  struct char_print_parms* p = (struct char_print_parms*) parameters;

  int i;

  for (i = 0; i < p->count; ++i)

    fputc (p->character, stderr);

  return NULL;

/* The main program.  */

int main ()

  pthread_t thread1_id;

  pthread_t thread2_id;

  struct char_print_parms thread1_args;

  struct char_print_parms thread2_args;

  /* Create a new thread to print 30000 x's.  */

  thread1_args.character = 'x';

  thread1_args.count = 30000;

  pthread_create (&thread1_id, NULL, &char_print, &thread1_args);

  /* Create a new thread to print 20000 o's.  */

  thread2_args.character = 'o';

  thread2_args.count = 20000;

  pthread_create (&thread2_id, NULL, &char_print, &thread2_args);

  /* Make sure the first thread has finished.  */

  pthread_join (thread1_id, NULL);

  /* Make sure the second thread has finished.  */

  pthread_join (thread2_id, NULL);

  /* Now we can safely return.  */

  return 0;

/***********************************************************************

* Code listing from "Advanced Linux Programming," by CodeSourcery LLC  *

* Copyright (C) 2001 by New Riders Publishing                          *

* See COPYRIGHT for license information.                               *

***********************************************************************/

#include

#include

#include

/* An array of balances in accounts, indexed by account number. Critical section */

float* account_balances;

/* Transfer DOLLARS from account FROM_ACCT to account TO_ACCT.  Return

   0 if the transaction succeeded, or 1 if the balance FROM_ACCT is

   too small.  */

int process_transaction (int from_acct, int to_acct, float dollars)

  int old_cancel_state;

  /* Check the balance in FROM_ACCT.  */

  if (account_balances[from_acct] < dollars)

    return 1;

  /* Begin critical section.  */

  pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, &old_cancel_state);

  /* Move the money.  */

  account_balances[to_acct] += dollars;

  account_balances[from_acct] -= dollars;

  /* End critical section.  */

  pthread_setcancelstate (old_cancel_state, NULL);

  return 0;