Change the Linux Port to use condition variables instead of Signals (#156)

* Posix port with pthread cond instead of signals
* Comment: replace signal with pthread_cond
Co-authored-by: Alfred Gedeon <gedeonag@amazon.com>
This commit is contained in:
alfred gedeon 2020-09-07 09:56:28 -07:00 committed by GitHub
parent 700c1cf9c6
commit 35f0b2ab84
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3 changed files with 126 additions and 95 deletions

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#include <pthread.h>
#include <stdlib.h>
#include <errno.h>
#include "wait_for_event.h"
struct event
{
pthread_mutex_t mutex;
pthread_cond_t cond;
bool event_triggered;
};
struct event * event_create()
{
struct event * ev = malloc( sizeof( struct event ) );
ev->event_triggered = false;
pthread_mutex_init( &ev->mutex, NULL );
pthread_cond_init( &ev->cond, NULL );
return ev;
}
void event_delete( struct event * ev )
{
pthread_mutex_destroy( &ev->mutex );
pthread_cond_destroy( &ev->cond );
free( ev );
}
bool event_wait( struct event * ev )
{
pthread_mutex_lock( &ev->mutex );
while( ev->event_triggered == false )
{
pthread_cond_wait( &ev->cond, &ev->mutex );
}
ev->event_triggered = false;
pthread_mutex_unlock( &ev->mutex );
return true;
}
bool event_wait_timed( struct event * ev,
time_t ms )
{
struct timespec ts;
int ret = 0;
clock_gettime( CLOCK_REALTIME, &ts );
//ts.tv_sec += ms;
ts.tv_nsec += (ms * 1000000);
pthread_mutex_lock( &ev->mutex );
while( (ev->event_triggered == false) && (ret == 0) )
{
ret = pthread_cond_timedwait( &ev->cond, &ev->mutex, &ts );
if( ( ret == -1 ) && ( errno == ETIMEDOUT ) )
{
return false;
}
}
ev->event_triggered = false;
pthread_mutex_unlock( &ev->mutex );
return true;
}
void event_signal( struct event * ev )
{
pthread_mutex_lock( &ev->mutex );
ev->event_triggered = true;
pthread_cond_signal( &ev->cond );
pthread_mutex_unlock( &ev->mutex );
}

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#ifndef _WAIT_FOR_EVENT_H_
#define _WAIT_FOR_EVENT_H_
#include <stdbool.h>
#include <time.h>
struct event;
struct event * event_create();
void event_delete( struct event * );
bool event_wait( struct event * ev );
bool event_wait_timed( struct event * ev,
time_t ms );
void event_signal( struct event * ev );
#endif /* ifndef _WAIT_FOR_EVENT_H_ */