方案2相对最好。
注释应该起到画龙点睛的作用，用于简要的描述代码意图；避免使用注释描述程序的运行流程。
让设备B定时重发RSP消息
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include "timer.h"
#define MAX 32
#define GAP 10
struct STimer
{
int id;
int interval;
int current;
int in_callback;
int to_delete;
TimerCallback* callback;
void* data;
};
static struct STimer* g_timers[MAX];
static volatile int g_run;
static pthread_mutex_t mutex;
static void* Runtime(void* args)
{
int i = 0;
while( g_run )
{
pthread_mutex_lock(&mutex);
for(i=0; (i<MAX) && g_run; i++)
{
struct STimer* st = g_timers[i];
if( (st != NULL) && (st->callback != NULL) )
{
st->current += GAP;
if( st->current >= st->interval )
{
st->in_callback = 1;
st->callback(st, st->data);
st->in_callback = 0;
st->current = 0;
if( st->to_delete )
{
g_timers[st->id] = NULL;
free(st);
}
}
}
}
pthread_mutex_unlock(&mutex);
usleep(GAP * 1000);
}
for(i=0; i<MAX; i++)
{
free(g_timers[i]);
}
}
void TimerInitialize()
{
if( !g_run )
{
pthread_t tid = 0;
g_run = 1;
pthread_create(&tid, NULL, Runtime, NULL);
}
}
void TimerFinalize()
{
g_run = 0;
}
Timer* CreateTimer(int interval, TimerCallback* callback, void* data)
{
int id = 0;
struct STimer* ret = (struct STimer*)malloc(sizeof(struct STimer));
if( ret != NULL )
{
pthread_mutex_lock(&mutex);
for(id=0; id<MAX; id++)
{
if( g_timers[id] == NULL )
{
g_timers[id] = ret;
break;
}
}
pthread_mutex_unlock(&mutex);
if( id < MAX )
{
ret->id = id;
ret->interval = interval;
ret->current = 0;
ret->to_delete = 0;
ret->in_callback = 0;
ret->callback = callback;
ret->data = data;
}
else
{
free(ret);
ret = NULL;
}
}
return ret;
}
void DestroyTimer(Timer* timer)
{
if( timer != NULL )
{
struct STimer* st = (struct STimer*)timer;
if( st->in_callback )
{
st->to_delete = 1;
}
else
{
pthread_mutex_lock(&mutex);
g_timers[st->id] = NULL;
pthread_mutex_unlock(&mutex);
free(st);
}
}
}
#ifndef _TIMER_H_
#define _TIMER_H_
typedef void Timer;
typedef void(TimerCallback)(Timer*, void*);
void TimerInitialize();
void TimerFinalize();
Timer* CreateTimer(int interval, TimerCallback* callback, void* data);
void DestroyTimer(Timer* timer);
#endif