From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Ye Liu" <yliu@tibco.com>
To: Wayne Isaacs <wisaacs@io.com>, pthreads-win32@sourceware.cygnus.com, pthreads-win32-info@sourceware.cygnus.com
Subject: Re: Using a class method as starting routine.
Date: Tue, 31 Jul 2001 12:09:00 -0000
Message-id: <3B670041.C193FA2D@tibco.com>
References: <3B65C795.A5680EC7@tibco.com> <000901c1196d$cd9ccea0$6601a8c0@stone>
X-SW-Source: 2001/msg00075.html

Thanks, Wayne.

I found my problem later after I posted the mail. Now my class is like:

/*    create.h    */
#ifndef _CREATE_H_
#define _CREATE_H_

#include <stdio.h>
#include "pthread.h"

class create
{
public:
 create();
 static void *thread_routine(void *arg)
{
    create *pObject = (create *)pObject;
    ...
}
 void start();
};

#endif

/*    create.cpp    */
#include "create.h"

void *create::thread_routine(void *arg)
{
 printf("The thread is here\n");
 return NULL;
}

void create::start()
{
 pthread_t thread_id;
 pthread_attr_t thread_attr;

 pthread_create(&thread_id, &thread_attr, create::thread_routine, (void *)this);

}

Pass this as the arg to the thread routine to enable it to access the
members/methods of the class: static function can only access the static
members/methods of the class. I feel it is an even better way in sense of Object
Oriented.

--ye


Wayne Isaacs wrote:

> I have never found a way to generate a usable function pointer from a
> non-static class method.  It may be theoretically incorrect to even try,
> because a non-static class method should not exist independently from the
> data object.
>
> On the other hand, if you declare the method 'static', then that method
> exists independent of data.  The compiler will let you generate and use a
> pointer to any static method.
>
> I would be interested to know Bjarne Stroustrup's preference on this issue,
> because the static function pointer required to launch thread routines is
> contrary to object orientation, but a fact of life for the major operating
> systems.
>
> I have written several thread classes.  Usually, the class object carries a
> thread function pointer and a termination event in private data.  The class
> defines the thread function pointer as a typedef.  The thread function takes
> two parameters; a void pointer for data, and an event pointer for
> termination.  That way, when the thread class object goes out of scope and
> destructs, it can gracefully terminate the thread.
>
> something like:
>
> class ThreadFn {
>
>     pthread_t thread_id;
>     HANDLE termination_event;
>
>     public:
>         typedef  long (*static_f_type)( HANDLE, void* );
>         ThreadFn( static_f_type );
>
>     };
>
> Wayne
>
> ----- Original Message -----
> From: "Ye Liu" <yliu@tibco.com>
> To: <pthreads-win32@sourceware.cygnus.com>;
> <pthreads-win32-info@sourceware.cygnus.com>
> Sent: Monday, July 30, 2001 4:46 PM
> Subject: Using a class method as starting routine.
>
> > Greets,
> >
> > A rather dump question: how to use a class method as a starting routine
> > of pthread_create().
> >
> > I have the following code:
> > /*    create.h    */
> > #ifndef _CREATE_H_
> > #define _CREATE_H_
> >
> > #include <stdio.h>
> > #include "pthread.h"
> >
> > class create
> > {
> > public:
> >  create();
> >  void *thread_routine(void *arg);
> >  void start();
> > };
> >
> > #endif
> >
> > /*    create.cpp    */
> > #include "create.h"
> >
> > void *create::thread_routine(void *arg)
> > {
> >  printf("The thread is here\n");
> >  return NULL;
> > }
> >
> > void create::start()
> > {
> >  pthread_t thread_id;
> >  pthread_attr_t thread_attr;
> >
> >  pthread_create(&thread_id, &thread_attr, create::thread_routine, NULL);
> >
> > }
> >
> > create::create()
> > {
> > }
> >
> > When I compiled it using VC6.0 (win32-pthread library of course), I got
> >
> > create.cpp
> > C:\ye\work\vs\pthread_projects\create\create.cpp(14) : error C2664:
> > 'pthread_create' : cannot convert parameter 3 from 'void *(void *)' to
> > 'void *(__cdecl *)(void *)'
> >         None of the functions with this name in scope match the target
> > type
> > Error executing cl.exe.
> >
> >
> > It seems that the compiler does not recognize thread_routine as a
> > address. Why does it happen? How to get around of it?
> >
> > Thanks a lot!
> >
> > --ye
> >
> >
> > --
> > Ye Liu
> > Tel(O) 650-846-5228
> >
> >

--
Ye Liu
Tel(O) 650-846-5228