2011年1月17日

之前看《高级Unix编程》说有基本定时器与高级定时器之分

好像基本定时器不符合我的要求，那么就先来个高级的吧。

写个代码看看会有什么发生：

2011年1月18日

看下timer_create函数

intt1;

timer_t tm_id;//timer_t其实是个long型t1 = timer_create(CLOCK_REALTIME, NULL, &tm_id);

cout << "timer_create return "<< t1 << endl;

cout << "tm_id"<< tm_id << endl;

intt2;

timer_t tm_id2;//timer_t其实是个long型t2 = timer_create(CLOCK_REALTIME, NULL, &tm_id2);

cout << "timer_create return "<< t2 << endl;

cout << "tm_id"<< tm_id2 << endl;

可看到输出的第一个time_id是0，第二个是1，其实就是用数字标识timerID啦。

2011年1月21日

今天终于试验出了个timer的用法：

下面是代码：

#include#include#includeusingstd::cout;

usingstd::endl;

voidalrm_handler(inti)

{

printf("timer interrupt %d/n",i);

time_t tm_show;

time(&tm_show);

cout << "settime : "<< (long)tm_show << "s "<< endl;

}

intmain()

{

intt1;

timer_t tm_id;//timer_t其?实?是?个?long型?t1 = timer_create(CLOCK_REALTIME, NULL, &tm_id);

cout << "timer_create return "<< t1 << endl;

cout << "tm_id"<< tm_id << endl;

intt2;

timer_t tm_id2;//timer_t其?实?是?个?long型?t2 = timer_create(CLOCK_REALTIME, NULL, &tm_id2);

cout << "timer_create return "<< t2 << endl;

cout << "tm_id"<< tm_id2 << endl;

cout << "set the timer "<< tm_id << ": 5s"<< endl;

cout << "set timer "<< tm_id2 << ": 3s"<< endl;

signal(SIGALRM,alrm_handler); //<>说?最?好?不?要?用?signal，?管?它?呢?，?这?个?简?单?，?用?sigacttion也?太?烦?了?吧?

//set timer 0 5sstructitimerspec itmspec;

structtimespec ts;

//struct sigaction sa;

//sigfillset(&sa.sa_mask);

//sa.sa_flags = SA_SIGINFO;

//sa.sa_sigaction = handler;itmspec.it_interval.tv_sec = 5;

itmspec.it_interval.tv_nsec = 0;

itmspec.it_value.tv_sec = 5;

itmspec.it_value.tv_nsec = 0;

time_t tm_show;

time(&tm_show);

timer_settime(tm_id, NULL,&itmspec,NULL);//第?二?个?参?数?为?，?则?与?setitimer相?似?，?第?四?个?参?数?返?回?旧?的?定?时?器?值?cout << "settime : "<< (long)tm_show << "s "<< endl;

itmspec.it_interval.tv_sec = 3;

itmspec.it_interval.tv_nsec = 0;

itmspec.it_value.tv_sec = 3;

itmspec.it_value.tv_nsec = 0;

timer_settime(tm_id2, NULL,&itmspec,NULL);

while(1);

return0;

}

makefile文件：

# # # # # # # # # # # # # # # # # # # # #

#  Makefile for pafone, general use

#                       2011.01.18

# # # # # # # # # # # # # # # # # # # # #

LIBS = -lrt

OBJS = main.o

TARGET = timer

#GCFLAGS :compile flags, GDFLAGS: link flags

GCFLAGS =

GDFLAGS =

GCC  = g++

all : $(OBJS)

$(GCC) -o $(TARGET) $(OBJS) $(LIBS)

@echo "compile success"

%.o : %.cpp

$(GCC) $(GCFLAGS) -c $< -o $@

clean :

rm -f $(TARGET) $(OBJS)

编译运行后的输出：

[root@pafone timer]# ./timer

timer_create return 0

tm_id0

timer_create return 0

tm_id1

set the timer 0: 5s

set timer 1: 3s

settime : 1295597124s

timer interrupt 14

settime : 1295597127s

timer interrupt 14

settime : 1295597129s

timer interrupt 14

settime : 1295597130s

timer interrupt 14

settime : 1295597133s

其中有一个是5s，另一个是3s的，但alrm_handler(inti)  函数传入来的i都是14，怎么区分是哪个定时器呢？    man 7 signal 发现里面的说明有说到handler的传入参数便是信号SIGALRM的#define值。

那么用sigacton可不可以区分是哪个定时器呢？还是一定要通过发送不同的信号来区分定时器？

注：信号会中断一些阻塞调用及sleep()函数，例如将while(1)改为sleep()

itmspec.it_interval.tv_sec = 3;

itmspec.it_interval.tv_nsec = 0;

itmspec.it_value.tv_sec = 3;

itmspec.it_value.tv_nsec = 0;

timer_settime(tm_id2, NULL,&itmspec,NULL);

sleep(100);

输出是：

[root@pafone timer]# ./timer

timer_create return 0

tm_id0

timer_create return 0

tm_id1

set the timer 0: 5s

set timer 1: 3s

settime : 1295599530s

timer interrupt 14

settime : 1295599533s

[root@pafone timer]#

即它会在第一个定时信号后返回，也就是定时信号中断了sleep.

如用用sigaction, 其它一些系统调用可以设置SA_RESTART使调用继续，但对sleep不起作用。