计时问题

leiwang_80

请问在C++里如何实现间隔50ms调用一个指定的函数，当然在时间间隔未满足50ms中间程序在执行其他操作。请高手指点，谢谢！

rollin7

这是C的实现，差不多的，你看看

void set_timer(void) {     struct itimerval tv;         tv.it_interval.tv_sec = 0;     tv.it_interval.tv_usec = 50*1000;     tv.it_value.tv_sec = 0;     tv.it_value.tv_usec = 50*1000;     (void)setitimer(ITIMER_REAL, &tv, NULL); } //####### 定时器事件#######// void func(void) { } //####### 创建定时器#######// void create_timer(void) {     sigact.sa_flags = 0;     sigact.sa_handler = (void *)func;     (void)sigaction(SIGALRM, &sigact, NULL);     set_timer(); }

[ 本帖最后由 rollin7 于 2009-9-10 22:00 编辑 ]

leiwang_80

sigact是什么？

leiwang_80

能否给一个完整的实例？谢谢！

原帖由 rollin7 于 2009-9-10 21:58 发表
这是C的实现，差不多的，你看看

void set_timer(void)
{
    struct itimerval tv;
   
    tv.it_interval.tv_sec = 0;
    tv.it_interval.tv_usec = 50*1000;
    tv.it_value.tv_sec = 0;
    t ...

unistd001

信号，，

rollin7

原帖由 leiwang_80 于 2009-9-13 18:03 发表
能否给一个完整的实例？谢谢！

晕，这已经是个完整实例了呀，在
sigact.sa_handler = (void *)func;
把func改成你对应的函数，再调用下create_timer()就OK了呀

leiwang_80

原帖由 rollin7 于 2009-9-13 20:54 发表


晕，这已经是个完整实例了呀，在
sigact.sa_handler = (void *)func;
把func改成你对应的函数，再调用下create_timer()就OK了呀

这是我调试的结果，在VC++6.0环境下编译未通过，请问什么原因？急！！！！！
#include <iostream.h>

void set_timer(void)
{
    struct itimerval tv;
   
    tv.it_interval.tv_sec = 0;
    tv.it_interval.tv_usec = 50*1000;
    tv.it_value.tv_sec = 0;
    tv.it_value.tv_usec = 50*1000;
    (void)setitimer(ITIMER_REAL, &tv, NULL);
}

//####### 定时器事件#######//
void myfunc(void)
{
        cout<<"timer is called!"<<endl;
}

//####### 创建定时器#######//
void create_timer(void)
{
    sigact.sa_flags = 0;
    sigact.sa_handler = (void *)myfunc;
    (void)sigaction(SIGALRM, &sigact, NULL);
    set_timer();
}

int main(){
        cout<<"timer"<<endl;
        while(1){
                cout<<"//////"<<endl;
                create_timer(void);
        }
        return 0;
}
--------------------Configuration: timer - Win32 Debug--------------------
Compiling...
timer.cpp
D:\实验\timer\timer.cpp(5) : error C2079: 'tv' uses undefined struct 'itimerval'
D:\实验\timer\timer.cpp(7) : error C2228: left of '.it_interval' must have class/struct/union type
D:\实验\timer\timer.cpp(7) : error C2228: left of '.tv_sec' must have class/struct/union type
D:\实验\timer\timer.cpp( : error C2228: left of '.it_interval' must have class/struct/union type
D:\实验\timer\timer.cpp( : error C2228: left of '.tv_usec' must have class/struct/union type
D:\实验\timer\timer.cpp(9) : error C2228: left of '.it_value' must have class/struct/union type
D:\实验\timer\timer.cpp(9) : error C2228: left of '.tv_sec' must have class/struct/union type
D:\实验\timer\timer.cpp(10) : error C2228: left of '.it_value' must have class/struct/union type
D:\实验\timer\timer.cpp(10) : error C2228: left of '.tv_usec' must have class/struct/union type
D:\实验\timer\timer.cpp(11) : error C2065: 'setitimer' : undeclared identifier
D:\实验\timer\timer.cpp(11) : error C2065: 'ITIMER_REAL' : undeclared identifier
D:\实验\timer\timer.cpp(23) : error C2065: 'sigact' : undeclared identifier
D:\实验\timer\timer.cpp(23) : error C2228: left of '.sa_flags' must have class/struct/union type
D:\实验\timer\timer.cpp(24) : error C2228: left of '.sa_handler' must have class/struct/union type
D:\实验\timer\timer.cpp(25) : error C2065: 'sigaction' : undeclared identifier
D:\实验\timer\timer.cpp(25) : error C2065: 'SIGALRM' : undeclared identifier
D:\实验\timer\timer.cpp(33) : error C2144: syntax error : missing ')' before type 'void'
D:\实验\timer\timer.cpp(33) : error C2059: syntax error : ')'
Error executing cl.exe.

timer.exe - 18 error(s), 0 warning(s)