create a thread from a returning function


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# 1  
create a thread from a returning function

hi all,
my requirement is to create a thread by calling another function.
i.e i dont call pthread_create directly from main, but by calling another function (createThd - below ), from main.
Example:
[CODE]

void *thread_function(void *arg) { /* thread function */
int i;
rc = pthread_detach(pthread_self());
for ( ; ; ) {
printf("Thread says hi!\n");
sleep(1);
}
pthread_exit(NULL);
}

int main(void) {

int i;
i = createThd(); /* call to thread creating function */

return (0);

}

int createThd()
{
int rc = 0;
pthread_t mythread;

if ( pthread_create( &mythread, NULL, thread_function, NULL) ) {
printf("error creating thread.");
return(-1);
}
return 0;
}
[\CODE]
this creates the thread but doesnt run it, thread terminates as soon as the function createThd() returns.
is there a way to overcome this problem.

any help is appreciated, thankx in advanced.
wolwy.
# 2  
The reason this is not working is that your main function doesn't have an event loop and/or doesn't block on the created thread.
An easy way out is to return the created thread tid, do not detach, and call pthread_join in main.

HTH.
# 3  
Quote:
Originally Posted by wolwy_pete
hi all,
my requirement is to create a thread by calling another function.
i.e i dont call pthread_create directly from main, but by calling another function (createThd - below ), from main.
Example:
Code:
void *thread_function(void *arg) {  /* thread function */
	int i;
	rc = pthread_detach(pthread_self());
	for ( ; ; )  {
		printf("Thread says hi!\n");
		sleep(1);
	}
	pthread_exit(NULL);
}

int main(void) {

	int i;
	i = createThd();  /* call to thread creating function */

	return (0);

}

int createThd()
{
	int rc = 0;
	pthread_t mythread;

	if ( pthread_create( &mythread, NULL, thread_function, NULL) ) {
		printf("error creating thread.");
		return(-1);
	}
	return 0;
}

this creates the thread but doesnt run it, thread terminates as soon as the function createThd() returns.
is there a way to overcome this problem.

any help is appreciated, thankx in advanced.
wolwy.
Hi,
You could wait on createThd() until thread_function() has done his job by means of pthread_cond_wait/pthread_cond_signal & mutexes, just like a parent process would wait (with wait/waitpid) for its child to terminate...
# 4  
thankx ramen_noodle & andryk Smilie
ramen_noodle was actually correct, sorry abt my lack of knowledge.
i put a loop in my main program and it was ok.
wolwy.
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