RU/2: Форум. Общение пользователей и разработчиков OS/2 (eCS). : Multithreading (IX)

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Example 2: A thread termination under C/2 with the standard function _endthread()

(1.) Prototype definition:

#include <stdlib.h> /* also defined in <process.h> */

void _endthread(void);

In the header file stdlib.h there are the definitions for the function _endthread()

(2.) Language Level: Extension

The _endthread function explicitly ends a thread anywhere where it is called in the function of the thread where you previously created it with _beginthread before the thread has completed its function.

For example, if some condition is not met, _endthread terminates the thread. When the thread has finished, it automatically ends itself with an implicit call to _endthread.
In other words: A thread can terminate itself either by returning from the main thread
function or by using and _endthread() anywhere in the execution of the thread.

Note:

1. When using the _beginthread and _endthread functions, you must specify the
/Gm+ compiler option to use the multithread libraries.

2. If you use DosCreateThread, you must explicitly call _endthread to
terminate the thread.

There is no return value of the function _endthread().

(3.)Programming example:

/************************************************************************
*
In this example, the main program creates two threads, bonjour
and au_revoir. The thread bonjour is forcibly terminated by a
call to _endthread, while the au_revoir thread ends itself with an
implicit call to _endthread.

Note: To run this example, you must compile it using the /Gm+
compile-time option.

*
************************************************************************/

#define INCL_DOS
#include <os2.h>
#include <stdio.h>
#include <stdlib.h>
#include <process.h>

void bonjour(void *arg)
{
int i = 0;
while ( i++ < 5 )
printf("Bonjour!\n");

_endthread(); /* This thread ends itself explicitly */
puts("thread should terminate before printing this");
}

void au_revoir(void *arg)
{
int i = 0;
while ( i++ < 5 ) /* This thread makes an implicit */
printf("Au revoir!\n"); /* call to _endthread */
}

int main(void)
{
unsigned long tid1;
unsigned long tid2;

tid1 = _beginthread(bonjour, NULL, 8192, NULL);
tid2 = _beginthread(au_revoir, NULL, 8192, NULL);

if ( (tid1 == -1) || (tid2 == -1) )
{
printf("Unable to start threads.\n");
exit(-1);
}

DosWaitThread( &tid2, DCWW_WAIT ); /* wait until threads 1 and 2 */
DosWaitThread( &tid1, DCWW_WAIT ); /* have been completed */

return 0;

/* Possible output could be:

Bonjour!
Au revoir!
Bonjour!
Au revoir!
Bonjour!
Au revoir!
Bonjour!
Au revoir!
Bonjour!
Au revoir! */

}

Remarks:

The return value of -1 from the function _beginthread means that the function ended
with an error.

In this example there are two thread functions definded. It is not sure in which order
the printout will happen! This case of two or more threads and its order of execution
will be shown in a further lesson.

A thread will also be terminated with a call of abort, return, DosExit, and a DosKillThread.

For the definitions of _beginthread() and DosWaitThread() see this reference: m019628.html

Sun 11 Jan 2004 15:02

Mozilla/4.61 [en] (OS/2; U)

Multithreading (IX) (???, 11.01.04 15:02)

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