Threads

gagan7230

The POSIX thread libraries are a standards based thread API for C/C++.
It allows one to spawn a new concurrent process flow. It is most effective
on multi-processor or multi-core systems where the process flow can be scheduled to run on
another processor thus gaining speed through parallel or distributed processing.
Threads require less overhead than "forking" or spawning a new process because
the system does not initialize a new system virtual memory space and environment for
the process. While most effective on a multiprocessor system, gains are
also found on uniprocessor systems which exploit latency in I/O and other
system functions which may halt process execution. (One thread may execute
while another is waiting for I/O or some other system latency.)
Parallel programming technologies such as MPI and PVM are used in a distributed
computing environment while threads are limited to a single computer system.
All threads within a process share the same address space.
A thread is spawned by defining a function and its arguments which will
be processed in the thread.
The purpose of using the POSIX thread library in your software is
to execute software faster

anubala331

/*hw pthread_join is used*/
2 #include<stdio.h>
3 #include<stdlib.h>
4 #include<pthread.h>
5 void* thread_fun1(void*);
6 void* thread_fun2(void*);
7 int main()
8 {
9     pthread_t tid,tid1;
10     char a[]="hello";
11     void* ret;
12     pthread_create(&tid,NULL,thread_fun1,(void*)a);
13     pthread_create(&tid1,NULL,thread_fun2,(void*)a);
14     //sleep(50);
15     pthread_join(tid1,&ret);//i m waiting for tid of 2nd process when it returned ..    .it will print that code....then continues..further
16 //    pthread_join(tid,&ret);
17     return 0;
18 }20 {
21     printf("anu\n");
22     printf("anu\n");
23     printf("anu\n");
24     printf("i=%d",(char*)i);
25     printf("anu\n");
26     pthread_exit("hi");
27 }
28 void* thread_fun2(void* i)
29 {
30     printf("yes\n");
31     printf("yes\n");
32     printf("yes\n");
33     printf("i=%d",(char*)i);
34     printf("yes\n");
35     pthread_exit("bye");
36     return 0;
37 }

19 void* thread_fun1(void* i)

anubala331

pthread_cancel(tid3);//to cancel the threads

Threads

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