omsTimer函数是处理定时事件，void(*handle)(union sigval v)参数就是处理事件的函数指针。
int omsSetTimer(timer_t *tId,int value,int interval)就是设置定时器。
按你说的，如果要同时起多个定时器，需要定义一个数组timer_t tm[n]int it[n]tm就是定时器结构，it用来记录对应的定时器是否已经使用，使用中的就是1，没用的就是0；
主进程消息来了就从it找一个没用的来omsSetTimer，如果收到终止消息，那omsSetTimer 定时时间为0
int omsTimer(timer_t *tId,int iValue,int iSeconds ,void(*handle)(union sigval v),void * param)
{
struct sigevent se
struct itimerspec ts
memset (&se, 0, sizeof (se))
se.sigev_notify = SIGEV_THREAD
se.sigev_notify_function = handle
se.sigev_value.sival_ptr = param
if (timer_create (CLOCK_REALTIME, &se, tId) <0)
{
return -1
}
ts.it_value.tv_sec = iValue
// ts.it_value.tv_sec =3
//ts.it_value.tv_nsec = (long)(iValue % 1000) * (1000000L)
ts.it_value.tv_nsec = 0
ts.it_interval.tv_sec = iSeconds
//ts.it_interval.tv_nsec = (long)(iSeconds % 1000) * (1000000L)
ts.it_interval.tv_nsec = 0
if (timer_settime(*tId, TIMER_ABSTIME, &ts, NULL) <0)
{
return -1
}
return 0
}
int omsSetTimer(timer_t *tId,int value,int interval)
{
struct itimerspec ts
ts.it_value.tv_sec =value
//ts.it_value.tv_nsec = (long)(value % 1000) * (1000000L)
ts.it_value.tv_nsec = 0
ts.it_interval.tv_sec = interval
//ts.it_interval.tv_nsec = (long)(interval % 1000) * (1000000L)
ts.it_interval.tv_nsec = 0
if (timer_settime(*tId, TIMER_ABSTIME, &ts, NULL) <0)
{
return -1
}
return 0
}
1. RTC(Real Time Clock)所有PC都有RTC. 它和CPU和其他芯片独立。它在电脑关机之后还可以正常运行。RTC可以在IRQ8上产生周期性中断. 频率在2Hz--8192HZ.Linux只是把RTC用来获取时间和日期. 当然它允许进程通过对/dev/rtc设备来对它进行编程。Kernel通过0x70和0x71 I/O端口来访问RTC。 2. TSC(Time Stamp Counter)80x86上的微处理器都有CLK输入针脚. 从奔腾系列开始. 微处理器支持一个计数器. 每当一个时钟信号来的时候. 计数器加1. 可以通过汇编指令rdtsc来得到计数器的值。通过calibrate_tsc可以获得CPU的频率. 它是通过计算大约5毫秒里tsc寄存器里面的增加值来确认的。或者可以通过cat /proc/cpuinfo来获取cpu频率。tsc可以提供比PIT更精确的时间度量。 3. PIT(Programmable internval timer)除了RTC和TSC. IBM兼容机提供了PIT。PIT类似微波炉的闹钟机制. 当时间到的时候. 提供铃声. PIT不是产生铃声. 而是产生一种特殊中断. 叫定时器中断或者时钟中断。它用来告诉内核一个间隔过去了。这个时间间隔也叫做一个滴答数。可以通过编译内核是选择内核频率来确定。如内核频率设为1000HZ,则时间间隔或滴答为1/1000=1微秒。滴答月短. 定时精度更高. 但是用户模式的时间更短. 也就是说用户模式下程序执行会越慢。滴答的长度以纳秒形式存在tick_nsec变量里面。PIT通过8254的0x40--0x43端口来访问。它产生中断号为IRQ 0.下面是关于pIT里面的一些宏定义：HZ：每秒中断数。CLOCK_TICK_RATE:值是1,193,182. 它是8254芯片内部振荡器频率。LATCH：代表CLOCK_TICK_RATE和HZ的比率. 被用来编程PIT。setup_pit_timer()如下：spin_lock_irqsave(&i8253_lock, flags)outb_p(0x34,0x43)udelay(10)outb_p(LATCH &0xff, 0x40)udelay(10)outb (LATCH >>8, 0x40)spin_unlock_irqrestore(&i8253_lock, flags) 4. CPU Local Timer最近的80x86架构的微处理器上的local apic提供了cpu local timer.他和pit区别在于它提供了one-shot和periodic中断。它可以使中断发送到特定cpu。one-shot中断常用在实时系统里面。个人解决了，以下是一个实现：#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <signal.h>
#include <string.h>
#include <pthread.h>
#include <time.h>
#if 1
pthread_attr_t attr
timer_t hard_timer, software_timer
struct sigevent hard_evp, software_evp
static void watchdog_hard_timeout(union sigval v)
{
time_t t
char p[32]
timer_t *q
struct itimerspec ts
int ret
time(&t)
strftime(p, sizeof(p), "%T", localtime(&t))
printf("watchdog hard timeout!\n")
printf("%s thread %d, val = %u, signal captured.\n", p, (unsigned int)pthread_self(), v.sival_int)
q = (timer_t *)(v.sival_ptr)
printf("hard timer_t:%d add:%p, q:%p!\n", (int)hard_timer, &hard_timer, q)
ts.it_interval.tv_sec = 0
ts.it_interval.tv_nsec = 0
ts.it_value.tv_sec = 6
ts.it_value.tv_nsec = 0
ret = timer_settime(*q, CLOCK_REALTIME, &ts, NULL)
if (ret != 0) {
printf("settime err(%d)!\n", ret)
}
}
static void watchdog_software_timeout(union sigval v)
{
time_t t
char p[32]
timer_t *q
struct itimerspec ts
int ret
time(&t)
strftime(p, sizeof(p), "%T", localtime(&t))
printf("watchdog software timeout!\n")
printf("%s thread %d, val = %u, signal captured.\n", p, (unsigned int)pthread_self(), v.sival_int)
q = (timer_t *)(v.sival_ptr)
printf("hard timer_t:%d add:%p, q:%p!\n", (int)hard_timer, &hard_timer, q)
ts.it_interval.tv_sec = 0
ts.it_interval.tv_nsec = 0
ts.it_value.tv_sec = 10
ts.it_value.tv_nsec = 0
ret = timer_settime(*q, CLOCK_REALTIME, &ts, NULL)
if (ret != 0) {
printf("settime err(%d)!\n", ret)
}
}
static void dcmi_sol_pthread_attr_destroy(pthread_attr_t *attr)
{
pthread_attr_destroy(attr)
}
static int dcmi_sol_pthread_attr_init(pthread_attr_t *attr)
{
int ret
if ((ret = pthread_attr_init(attr) != 0)) {
goto err
}
if ((ret = pthread_attr_setdetachstate(attr, PTHREAD_CREATE_DETACHED)) != 0) {
dcmi_sol_pthread_attr_destroy(attr)
goto err
}
/* 设置线程的栈大小,失败则用系统默认值 */
pthread_attr_setstacksize(attr, 128 * 1024)
return 0
err:
printf("set ptread attr failed(ret:%d)!\n", ret)
return -1
}
int main(void)
{
struct itimerspec ts
int ret
ret = dcmi_sol_pthread_attr_init(&attr)
if (ret != 0) {
printf("init pthread attributes fail(%d)!\n", ret)
exit(-1)
}
memset(&hard_evp, 0, sizeof(struct sigevent))
hard_evp.sigev_value.sival_ptr = &hard_timer
hard_evp.sigev_notify = SIGEV_THREAD
hard_evp.sigev_notify_function = watchdog_hard_timeout
hard_evp.sigev_notify_attributes = NULL//&attr
memset(&software_evp, 0, sizeof(struct sigevent))
software_evp.sigev_value.sival_ptr = &software_timer
software_evp.sigev_notify = SIGEV_THREAD
software_evp.sigev_notify_function = watchdog_software_timeout
software_evp.sigev_notify_attributes = NULL//&attr
ret = timer_create(CLOCK_REALTIME, &hard_evp, &hard_timer)
if(ret != 0) {
perror("hard timer_create fail!")
exit(-1)
}
ret = timer_create(CLOCK_REALTIME, &software_evp, &software_timer)
if (ret != 0) {
timer_delete(hard_timer)
perror("software timer_create fail!")
exit(-1)
}
ts.it_interval.tv_sec = 0
ts.it_interval.tv_nsec = 0
ts.it_value.tv_sec = 6
ts.it_value.tv_nsec = 0
ret = timer_settime(hard_timer, CLOCK_REALTIME, &ts, NULL)
if(ret != 0) {
perror("hard timer_settime fail!")
timer_delete(hard_timer)
timer_delete(software_timer)
exit(-1)
}
ts.it_value.tv_sec = 10
ret = timer_settime(software_timer, CLOCK_REALTIME, &ts, NULL)
if(ret != 0) {
perror("hard timer_settime fail!")
timer_delete(hard_timer)
timer_delete(software_timer)
exit(-1)
}
while(1) {
printf("main ready sleep!\n")
sleep(15)
printf("main sleep finish!\n")
}
return 0
}
#endif
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