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Full Discussion: How Can I use pthread_create ?
Top Forums Programming How Can I use pthread_create ? Post 302174543 by tellarunbose on Tuesday 11th of March 2008 11:22:36 AM
Old 03-11-2008
MySQL hay try this cpp code to thread member functions!!!!!
as u know threads are called by simple calling a static function.

but member functions are restricted to the scope of an object as they access on variables within an object specific environment.

so one of the best way to do this is a JAVA style generic threading architecture- i hav provided a simple code here---njoy!!!!!

~~~~~~~~~~~~~~~~~~~~~

Code:
#include<iostream>
#include<pthread.h>
#include<sys/types.h>

using namespace std;

// this class is used to make generic calls to the run function
// in any object which have been inherited from object class

class Object
{
    public:
      virtual void run(){}
};

// now we will create an executer non member function
//which can call the run function of any Object class instance

void* executer(void* param)
{
   Object *obj=(Object*)param;
   obj->run();
   // this will definitely call the run function associated with the object obj
   // from this general function--the rest i guess u can figure out!
}

//now we will create the threading framework

class thread : public Object
{
  pthread_t thid;
  int ret;
  public:
   void start();
   void join();
};

// this member function will call the run function of the derived class
void thread::start()
{
   ret=pthread_create(&thid,NULL,executer,(void*)this);
}
// this is to join the object threads
void thread::join()
{
   pthread_join(thid,NULL);
}

//~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// thats all thats required for the basic one
// now we use the above code...
// if we have to call a member function of a class
// we inherit it from the class thread and call the derived calss object //start function
// the run function will get executed as a thread!!!! just as java does it
// note that only the run function is threadable here
// further modifications is up to u - this is only the base
// by the way i hav not provided nything for synchronisation-give it where
//required, alogo to pass arg to threads, calling functions other than the //run() etc....
//  as an example of the above frame work we shall see a small example
//~~~~~~~~~~~~~~~~~~~~~~~~~~~~

class multicount : public thread
{
   char *name;
  public:
    multicount(char n[])
    {
      name=n;
    }
    void run();
};
void multicount::run()
{
   for(int i=0;i<10000;i++)
   {
     cout<<"\n"<<name<<" : "<<i;
   }
}

int main()
{
  // we first create 3 instances(objects) of multicount a,b,c
  multicount a("thread1"),b("thread2"),c("thread3");
  // then we call the a.start() of object a to create a thread for doing  
  // a.run() and similarly for others
  a.start();
  b.start();
  c.start();
  // finally we wait for all threads to join
  a.join();
  b.join();
  c.join();

  //creating such frameworks greatly reduces programming difficulty with 
  // OOP
  // see how eazy the thread operations became with the simple 
  //architecture

  return 0;
}

Last edited by Franklin52; 12-27-2008 at 07:30 AM.. Reason: adding code tags
 

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LEARN ABOUT HPUX

pthread_create

pthread_create(3T)														pthread_create(3T)

NAME

       pthread_create() - create a new thread of execution.

SYNOPSIS

PARAMETERS

	      thread	Pointer to the location where the created thread's ID is to be returned.

	      attr	Pointer  to  the  thread  attributes  object  describing  the characteristics of the created thread. If the value is NULL,
			default attributes will be used.

	      start_routine
			Function to be executed by the newly created thread.

	      arg	Parameter to be passed to the created thread's start_routine.

DESCRIPTION

       The function is used to create a new independent thread within the calling process.  The thread will be created according to the attributes
       specified  by  attr.  If attr is NULL, the default attributes will be used.  The values of the attributes in attr describe the characteris-
       tics of the to-be-created thread in detail.  Refer to the function for a list of the default attribute values.  A single attributes  object
       can be used in multiple calls to the function

       When  a	thread	is  created  with  an attributes object, the attributes are, in effect, copied into the created thread.  Consequently, any
       change to the attributes object will not affect any previously created threads.	Once all threads needing a specific attributes object have
       been created, the attributes object is no longer needed and may be destroyed.

       When  the  new  thread is created, it will execute which has only one parameter, arg.  If returns, an implicit call to is made.	The return
       value of is used as the thread's exit status.

       The created thread's scheduling policy and priority, contention scope, detach state, stack size, and stack address are initialized  accord-
       ing  to	their respective attributes in attr.  The thread's signal mask is inherited from the creating thread.  The thread's set of pending
       signals is cleared.

       Refer to pthread_exit(3T), pthread_detach(3T), and pthread_join(3T) for more information on thread termination and synchronizing with  ter-
       minated threads.

       On  success,  the  ID  of the created thread is returned in thread.  If fails, a thread is not created and the contents of thread are unde-
       fined.

       Thread IDs are guaranteed to be unique only within a process.

       NOTE: If the main thread returns from an implicit call to is made.  The return value of is used as the  process'  exit  status.	 The  main
       thread can terminate without causing the process to terminate by calling

   Notes
       It is unspecified whether joinable threads that have exited but haven't been joined count against the limit.

RETURN VALUE

       Upon successful completion, returns zero. Otherwise, an error number is returned to indicate the error (the variable is not set).

ERRORS

       If any of the following occur, the function returns the corresponding error number:

	      attr	     in an invalid thread attributes object.

	      The value specified by
			     thread is invalid.

	      The necessary resources to create another thread are not available,
			     or the number of threads in the calling process already equals

	      The scheduling policy or scheduling attributes specified in
			     attr are invalid.

	      The caller does not have the appropriate privileges to create a thread with
			     the scheduling policy and parameters specified in attr.

AUTHOR

       was derived from the IEEE POSIX P1003.1c standard.

SEE ALSO

       pthread_exit(3T), pthread_join(3T), fork(2).

STANDARDS CONFORMANCE

								  Pthread Library						pthread_create(3T)
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