c,multithreading,pthreads , Pthread id and sleep


Pthread id and sleep

Question:

Tag: c,multithreading,pthreads

I need to do the following: Create a thread that creates 10 threads in a row. Each thread just prints it's ID and sleeps for n seconds, where n is the serial number of current thread. But, I can't get passing arguments right, when I run my code it seems like the thread is just sleeping.. Some help, please?

Here is my code:

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
# define N 10

void* printID (void *i)
{
int* p=(int*) i;
sleep(p);
pthread_exit(NULL);
}

void* th (void* unused)
{
int sec,i;
sec=1;
i=1;

while(i<=10){
pthread_t pid1;
pthread_create (&pid1, NULL, &printID, (void *)&i);
pthread_join(pid1,NULL);
printf("Thread ID je: %d \n",(int) pid1);

i=i+1;
}
}

int main(){

pthread_t pid;

pthread_create (&pid, NULL, &th, NULL);
pthread_join(pid,NULL);

return 0;
}

Answer:

Your argument passing is fine. But you are not passing the value to sleep.

It should be

sleep(*p);

p points the address of i (from the function th()). You need to dereference the pointer to get the value.


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