老大前几天提到libuv,我只看过一点libevent, 听说过libev,没听说过libuv,查了一下才知道libuv。
先到github git clone 源码,编译,测试,看测试代码
头文件uv.h定时器部分的函数,头文件有详细的注释
* uv_timer_t is a subclass of uv_handle_t.
*
* Used to get woken up at a specified time in the future.
*/
struct uv_timer_s {
UV_HANDLE_FIELDS
UV_TIMER_PRIVATE_FIELDS
};
UV_EXTERN int uv_timer_init(uv_loop_t*, uv_timer_t* handle);
/*
* Start the timer. `timeout` and `repeat` are in milliseconds.
*
* If timeout is zero, the callback fires on the next tick of the event loop.
*
* If repeat is non-zero, the callback fires first after timeout milliseconds
* and then repeatedly after repeat milliseconds.
*/
UV_EXTERN int uv_timer_start(uv_timer_t* handle,
uv_timer_cb cb,
uint64_t timeout,
uint64_t repeat);
UV_EXTERN int uv_timer_stop(uv_timer_t* handle);
/*
* Stop the timer, and if it is repeating restart it using the repeat value
* as the timeout. If the timer has never been started before it returns -1 and
* sets the error to UV_EINVAL.
*/
UV_EXTERN int uv_timer_again(uv_timer_t* handle);
/*
* Set the repeat value in milliseconds. Note that if the repeat value is set
* from a timer callback it does not immediately take effect. If the timer was
* non-repeating before, it will have been stopped. If it was repeating, then
* the old repeat value will have been used to schedule the next timeout.
*/
UV_EXTERN void uv_timer_set_repeat(uv_timer_t* handle, uint64_t repeat);
UV_EXTERN uint64_t uv_timer_get_repeat(const uv_timer_t* handle);
- /* uv_timer_test.c */
- #include <stdlib.h>
- #include <uv.h>
- #include <stdio.h>
- #include <assert.h>
- #include <time.h>
- static void timer_cb(uv_timer_t *handle, int status)
- {
- static int count;
- printf("count %d now %d\n", count++, time(NULL));
- }
- int main(int argc, char *argv[])
- {
- int r;
- uv_timer_t timer;
- r = uv_timer_init(uv_default_loop(), &timer);
- assert(r == 0);
- assert(!uv_is_active((uv_handle_t *) &timer));
- assert(!uv_is_closing((uv_handle_t *) &timer));
- printf("start %d\n", time(NULL));
- r = uv_timer_start(&timer, timer_cb, atoi(argv[1]), 0);
- r = uv_run(uv_default_loop(), UV_RUN_DEFAULT);
- assert(r == 0);
- return 0;
- }
测试程序流程非常简单,
初始化定时器uv_timer_init
注册自己的定时回调函数uv_timer_start
运行 uv_run
编译:gcc -o test-uv-timer test_uv_timer.c -luv
注意在uv_timer_start函数的参数repeat设置为1的话,time_cb在第一次定时时间到后之后会一直回调
最后贴上修改的test-acitive.c代码,从这个测试代码和uv.h的函数注释基本可以学会使用定时器的使用。
- #include <uv.h>
- #include <assert.h>
- #include <stdio.h>
- #include <stdlib.h>
- #define ASSERT assert
- static int close_cb_called = 0;
- static void close_cb(uv_handle_t* handle) {
- ASSERT(handle != NULL);
- close_cb_called++;
- }
- static void timer_cb(uv_timer_t* handle, int status) {
- ASSERT(0 && "timer_cb should not have been called");
- }
- int main()
- {
- int r;
- uv_timer_t timer;
- r = uv_timer_init(uv_default_loop(), &timer);
- ASSERT(r == 0);
- ASSERT(!uv_is_active((uv_handle_t*) &timer));
- ASSERT(!uv_is_closing((uv_handle_t*) &timer));
- r = uv_timer_start(&timer, timer_cb, 1000, 0);
- ASSERT(r == 0);
- ASSERT(uv_is_active((uv_handle_t*) &timer));
- ASSERT(!uv_is_closing((uv_handle_t*) &timer));
- r = uv_timer_stop(&timer);
- ASSERT(r == 0);
- ASSERT(!uv_is_active((uv_handle_t*) &timer));
- ASSERT(!uv_is_closing((uv_handle_t*) &timer));
- r = uv_timer_start(&timer, timer_cb, 1000, 0);
- ASSERT(r == 0);
- ASSERT(uv_is_active((uv_handle_t*) &timer));
- ASSERT(!uv_is_closing((uv_handle_t*) &timer));
- uv_close((uv_handle_t*) &timer, close_cb);
- ASSERT(!uv_is_active((uv_handle_t*) &timer));
- ASSERT(uv_is_closing((uv_handle_t*) &timer));
- r = uv_run(uv_default_loop(), UV_RUN_DEFAULT);
- ASSERT(r == 0);
- ASSERT(close_cb_called == 1);
- return 0;
- }