Re: [rtl] Linux equivalents to pthread_make_periodic_np and pthread_suspend_np

[David Schleef]

On Fri, Apr 13, 2001 at 09:22:14PM +0200, Ivan Martinez wrote:
> Hello all:
> I'm trying to make DSLib v2 generate adecuated system calls depending on it being 
>Linux, RTLinux, or RTAI. I'm looking in the Linux threads functions and I don't see 
>any equivalent to pthread_make_periodic_np and pthread_suspend_np. Is there any?. If 
>not, how can I perform such operations?.
> Thank you.
> Ivan Martinez


It can be duplicated using something similar to the attached
file.



dave...



/* Example of a periodic task using straight POSIX calls. */
/* Copyright 2001 David Schleef <[EMAIL PROTECTED]> */
/* Use, distribution, and modification are allowed under the LGPL. */

#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>


#define PERIOD 100000	/* 100 ms */

void tv_add_usec(struct timeval *tv,unsigned int usec);
int tv_compare(struct timeval *a,struct timeval *b);
void tv_sub(struct timeval *a,struct timeval *b);

int main(int argc,char *argv[])
{
	struct timeval now;
	struct timeval next_tick;

	gettimeofday(&next_tick,NULL);
	tv_add_usec(&next_tick,PERIOD);
	while(1){
		printf("tick\n");

		gettimeofday(&now,NULL);
		if(tv_compare(&next_tick,&now)<0){
			struct timeval timeout;

			timeout = next_tick;
			tv_sub(&timeout,&now);
			select(0,NULL,NULL,NULL,&timeout);
		}
		tv_add_usec(&next_tick,PERIOD);
	}
}

void tv_add_usec(struct timeval *tv,unsigned int usec)
{
	tv->tv_usec += usec;
	while(tv->tv_usec>=1000000){
		tv->tv_usec -= 1000000;
		tv->tv_sec ++;
	}
}

int tv_compare(struct timeval *a,struct timeval *b)
{
	if(a->tv_sec==b->tv_sec)return b->tv_usec-a->tv_usec;
	return b->tv_sec-a->tv_sec;
}

void tv_sub(struct timeval *a,struct timeval *b)
{
	a->tv_sec -= b->tv_sec;
	if(a->tv_usec < b->tv_usec){
		a->tv_usec += 1000000;
		a->tv_sec --;
	}
	a->tv_usec -= b->tv_usec;
}