Programming

..... variables here ....

if (pipe(tub) < 0) panic("Creació pipe");  /* pipe creation */
 
   switch (fork()) /* First child will exec Cat */ 
   { 
    
    case -1: panic("Fork 1"); 
     
    case 0: 
     
    close(1); dup(tub[1]); 
    close(tub[0]); close(tub[1]); 
     
    arg_list[0] = "cat";       /* Input files for Cat */
    for (p=0; p<Nfitxers; p++) { 
    pid = Pids[p]; 
    sprintf(s, "%d_Winners.txt", pid); 
    arg_list[p+1]= strdup(s); 
    } 
     
    arg_list[Nfitxers]= NULL; 
     
    execv("/bin/cat", arg_list);  /* Execute Cat here */
    panic("Executant execv cat"); 
 
    
    default: 
    break; 
   } 
    
   switch (fork()) /* Second child execut Sort */ 
   { 
    
    case -1: panic("Fork 2"); 
     
    case 0: 
     
    close(0); dup(tub[0]); 
    close(tub[0]);  
 
/* Creating Output file here */

    if ((dest = open("Winners.txt", O_WRONLY|O_TRUNC|O_CREAT, 0600))<0) { 
       panic("Creació del fitxer destí"); } 
 
     
    dup2(dest,STDOUT_FILENO);    /* Redirect output to file */
    dup2(dest,STDERR_FILENO);  
    close(dest);  
     
    execl( "sort" , "sort", NULL );   /* Executing sort */
    panic("Executant execl sort"); 
 
     
    default: 
    break; 
    
   } 
    
   close(tub[0]);  
   close(tub[1]); 
    
    
   wait(&st1); 
   wait(&st2);