using timer and signal instead of sleep c/c++ - c++

Question

I am working on multi threaded code, in which thread has to sleep for particular time. I don't want to wast CPU cycles and want to / have to use timers. This is more or less what I want achieve.
My single threaded code seems to be working fine.
#include <cstdlib>
#include <iostream>
#include <time.h>
#include <sys/siginfo.h>
#include <signal.h>
#include <unistd.h>
volatile sig_atomic_t print_flag = false;
void handle_alarm(int sig)
{
print_flag = true;
}
int main(int argc, char *argv[])
{
//struct sigevent event;
signal( SIGALRM, handle_alarm ); // Install handler first,
timer_t timerid;
struct itimerspec timer;
timer_create(CLOCK_REALTIME,NULL,&timerid);
timer.it_value.tv_sec = 1;
timer.it_value.tv_nsec = 0;
timer.it_interval.tv_sec = 0;
timer.it_interval.tv_sec = 0;
std::cout << "Setting timer" << std::endl;
timer_settime(timerid,0,&timer,NULL);
pause();
std::cout << "Hello\n" << std::endl;
return EXIT_SUCCESS;
}
But my multi threaded is stuck in execution. My main thread is stuck at waiting for threads and thread1 is stuck at setting timer. Any idea why thread1 is not completing execution?
#include <cstdlib>
#include <iostream>
#include <time.h>
#include <sys/siginfo.h>
#include <signal.h>
#include <unistd.h>
#include <pthread.h>
volatile sig_atomic_t print_flag = false;
void handle_alarm(int sig)
{
print_flag = true;
}
void *mythread(void* time)
{
signal( SIGALRM, handle_alarm ); // Install handler first,
timer_t timerid;
struct itimerspec timer;
timer_create(CLOCK_REALTIME,NULL,&timerid);
timer.it_value.tv_sec = *(int*)time;
timer.it_value.tv_nsec = 0;
timer.it_interval.tv_sec = 0;
timer.it_interval.tv_sec = 0;
std::cout << "Setting timer" << std::endl;
timer_settime(timerid,0,&timer,NULL);
pause();
std::cout << "Hello" << *(int*)time << std::endl;
}
int main(int argc, char *argv[])
{
pthread_t thread1, thread2;
std::cout << "Started threads\n" << std::endl;
int temp1 = 10,temp2 = 5;
pthread_create(&thread1, NULL, &mythread,(void*) &temp1);
pthread_create(&thread2, NULL, &mythread,(void*) &temp2);
std::cout << "Waiting for threads\n" << std::endl;
pthread_join(thread1,NULL);
pthread_join(thread2,NULL);
std::cout << "Done\n" << std::endl;
return EXIT_SUCCESS;
}
Edit:
I did it by few methods,
by using nanosleep, it just overcomes one problem, busy wait.
using clock_nanosleep, it is similar to nanosleep except it uses relative clock
Using timer_settime (pulse), the thread waits for pulse for given time and finally clocks out

Answer 1

I did it like this
struct sigevent event;
struct itimerspec itime;
timer_t timer_id;
int chid, rcvid;
my_message_t msg;
chid = ChannelCreate(0);
// following code is used to get kick every pulse period time
// which is 20ms
event.sigev_notify = SIGEV_PULSE;
event.sigev_coid = ConnectAttach(ND_LOCAL_NODE, 0,
chid,
_NTO_SIDE_CHANNEL, 0);
event.sigev_priority = getprio(0);
event.sigev_code = _PULSE_CODE_MINAVAIL;
timer_create(CLOCK_REALTIME, &event, &timer_id);
// 20 ms to nano seconds
itime.it_value.tv_sec = 0;
itime.it_value.tv_nsec = 20000000;
itime.it_interval.tv_sec = 0;
itime.it_interval.tv_nsec = 20000000;
timer_settime(timer_id, 0, &itime, NULL);
SERVO1DELAY1.tv_sec = 0;
SERVO1DELAY1.tv_nsec = 100000;
while(1)
{
rcvid = MsgReceive(chid, &msg, sizeof(msg), NULL);
if (rcvid == 0)
{
// make pulse high for appropriate time
out8( data_handle_A, HIGH );
InterruptDisable();
nanospin(&SERVO1DELAY1);
InterruptEnable();
out8( data_handle_A, LOW );
}
}