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libuv库使用过程中,发现简单的定时器不关闭对应的句柄会导致内存泄漏;使用文章后面的测试代码缺少uv_close或者uv_loop_close均会导致内存泄漏,关闭的时机也有影响。
Detected memory leaks!
Dumping objects -> {185} normal block at 0x00FB7860, 32 bytes long. Data: < R z > E8 52 E8 7A 00 00 00 00 00 00 00 00 00 00 00 00 {184} normal block at 0x00FB7818, 8 bytes long. Data: < > 00 00 00 00 00 00 00 00 {183} normal block at 0x00FB77A8, 48 bytes long. Data: < > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Object dump complete.
使用VS2010进行调试
1 设置项目依赖 2 添加泄漏位置的断点 _CrtSetBreakAlloc(185); 根据泄漏报告的位置确定,本例中有3处泄漏, 185, 184, 183,需要调试3次3 调试代码
打开调用堆栈,发现这里分配的内存4 * 8刚好32字节 uv_default_loop ->uv_loop_init ->uv__loops_add ->uv__realloc 而这块内存是在uv_loop_close->uv__loop_close->uv__loops_remove中释放的。同样的方法把分两次设置新的断点位置_CrtSetBreakAlloc(184);_CrtSetBreakAlloc(183);
发现uv_loop_init中有其他两处内存分配loop->timer_heap = timer_heap = uv__malloc(sizeof(*timer_heap));
lfields = (uv__loop_internal_fields_t*) uv__calloc(1, sizeof(*lfields));
4 解决内存泄漏问题
在头文件查找uv_loop_init,发现有成对的uv_loop_close,在loop结束后调用再次运行发现没有泄漏,问题得到解决,网上找的实例很多都没有说明。UV_EXTERN int uv_loop_init(uv_loop_t* loop);UV_EXTERN int uv_loop_close(uv_loop_t* loop);
测试代码如下
///*在入口函数中包含 _CrtDumpMemoryLeaks(); 即可检测到内存泄露*/#define CRTDBG_MAP_ALLOC #include#include #ifdef _DEBUG #define new new(_NORMAL_BLOCK, __FILE__, __LINE__) #endif //#include "stdafx.h"#include "uv.h"unsigned int g_tick;unsigned int g_count = 3;void time_cb(uv_timer_t* handle){ unsigned int now = GetTickCount(); printf("last:%lu, now:%lu, time:%lu\n", g_tick, now, now - g_tick); g_tick = now; if (--g_count <= 0) { uv_timer_stop(handle); uv_close((uv_handle_t*)handle, NULL); }}void EnableMemLeakCheck() { int tmpFlag = _CrtSetDbgFlag(_CRTDBG_REPORT_FLAG); tmpFlag |= _CRTDBG_LEAK_CHECK_DF; _CrtSetDbgFlag(tmpFlag); } int _tmain(int argc, _TCHAR* argv[]){ EnableMemLeakCheck(); _CrtSetBreakAlloc(185); //根据泄漏报告的位置确定,本例中有3处泄漏, 185, 184, 183,需要调试3次 /*使用默认loop*/ uv_loop_t *loop = uv_default_loop(); /*创建一个uv_timer_t对象timer*/ uv_timer_t timer; if (loop == NULL) { printf("init fail, loop:%p\n", loop); return -1; } /*初始化全局变量*/ g_tick = GetTickCount(); /*输出libuv版本*/ printf("uv version:%s\n", uv_version_string()); /*关联timer到loop*/ uv_timer_init(loop, &timer); /*设置定时器参数,包括回调函数,超时时间和重复时间,单位是毫秒*/ uv_timer_start(&timer, time_cb, 1000, 1000); /*loop跑起来*/ uv_run(loop, UV_RUN_DEFAULT); printf("uv_loop_close ...\n"); /*调试内存泄漏时需要注释掉*/ uv_loop_close(loop); getchar(); return 0;}
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