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：
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。
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
# .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。
