Posix threads

[Behnaz]

Hi,
consider the code below:

#include <stdio.h>
      .
      .

struct myStruct
{  
   char *message ;
   int id;
 };
     .    
     .
     .
void *thread_function( void *ptr );
nt main()
{
     pthread_t thread1, thread2 ,thread3 ;
     struct myStruct nico1;
     struct myStruct nico2;
     struct myStruct nico3;
     nico1.message="Thread1";
     nico1.id=0;
     nico2.message="Thread 2";
     nico2.id=1;
     nico3.message="Thread 3";
     nico3.id=2;
     int  iret1, iret2,iret3;
 
     iret1 = pthread_create( &thread1, NULL, thread_function, (void*)&nico1);
     iret2 = pthread_create( &thread2, NULL, thread_function, (void*)&nico2 );
     iret3= pthread_create( &thread3, NULL, thread_function, (void*)&nico3);
       .
       .
       .
     pthread_join( thread1, NULL);
     pthread_join( thread2, NULL);
     pthread_join( thread3, NULL); 
     
     exit(0);
}


void *thread_function( void *ptr )
{
    int k,j;
    struct myStruct *nico;
         nico=( struct myStruct*)ptr;
    k=1;
    while(k<10)
    {
        printf(" THREAD # %d \n", nico->id);
        printf("****************** \n ******************");
        printf("                    \n ");
        printf("in loop while k=%d : \n ",k);
        printf("                    \n ");
        printf("                    \n ");
        
        
        //then for j=1,...,k-1
                for(j=(nico->id); j<k; j+=3)  //Start at 0 for C
                {
            
            
            printf(" in loop for j=%d : \n ",j);
            printf("                    \n ");
    
                }
        
        
        k=k+1;
    }
 return NULL;
}

[pludi]

First, please put [code ][/code] tags (sans the space) around your listing, it's easier on the eyes. And since we're on the subject, could you shorten your output?

Second: Your thread has to run 8 printf()s, which translates to about 25 system instructions, times 10 = 250 instructions. Given that even a P90 from the last century can do roughly 90000000 instructions per second, your code is done long before the kernel has any reason to preempt it.

[fpmurphy]

You need to create your threads as joinable i.e.

pthread_attr_t attr;
....
pthread_attr_init(&attr);
pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
....
pthread_create( &thread1, &attr, thread_function, (void*)&nico1);
....