Intptr的释放问题

jonas401 2009-03-26 09:44:08

C#中申请内存大概有两种方式：
1 IntPtr Marshal.AllocHGlobal(int), 使用Marshal.FreeHGlobal(IntPtr)释放
2 IntPtr Marshal.AllocCoTaskMem(int), 使用Marshal.FreeCoTaskMem(IntPtr)释放

问题：
1 这两种内存方式有什么区别？哪种情况下使用哪种分配方式？
2 在下面这段代码中，是使用何种内存分方式？还是只是类型转换而未重新分析空间?
...
fixed (Int32* ptr = &CMD)
{
Marshal.Copy(new IntPtr(ptr), buffer, pos, size);
}
...

...全文

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切换为时间正序

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jonas401 2009-03-26

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OK，清楚了

kongdelu2008 2009-03-26

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[Quote=引用 4 楼 gomoku 的回复:]
CoTaskMemAlloc和CoTaskMemFree API一般用在COM交互的情况下。
而Marshal.FreeCoTaskMem(IntPtr)可以释放CoTaskMemAlloc申请的内存。

LocalAlloc和LocalFree API则可对应于Marshal.AllocHGlobal/Marshal.FreeHGlobal
[/Quote]
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gomoku 2009-03-26

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CoTaskMemAlloc和CoTaskMemFree API一般用在COM交互的情况下。
而Marshal.FreeCoTaskMem(IntPtr)可以释放CoTaskMemAlloc申请的内存。

LocalAlloc和LocalFree API则可对应于Marshal.AllocHGlobal/Marshal.FreeHGlobal

gomoku 2009-03-26

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只是类型转换

jonas401 2009-03-26

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人呢

格拉 2009-03-26

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//创建初始化播放器资源 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] extern public static IntPtr libvlc_new(int argc, IntPtr argv); //创建播放器实例 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern IntPtr libvlc_media_player_new(IntPtr libvlc_instance); // 释放libvlc实例 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_release(IntPtr libvlc_instance); //获取库版本信息 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern String libvlc_get_version(); // 从视频来源(例如Url)构建一个libvlc_meida RTSP [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern IntPtr libvlc_media_new_location(IntPtr libvlc_instance, IntPtr path); // 从本地文件路径构建一个libvlc_media rtsp串流不适合调用此接口 // [MarshalAs(UnmanagedType.LPStr)] string path [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern IntPtr libvlc_media_new_path(IntPtr libvlc_instance, IntPtr path); /// /// 影片长度 /// /// /// [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern IntPtr libvlc_media_player_get_length(IntPtr libvlc_media_player); //释放对象 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_media_release(IntPtr libvlc_media_inst); // 将视频(libvlc_media)绑定到播放器上 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_media_player_set_media(IntPtr libvlc_media_player, IntPtr libvlc_media); //创建(libvlc_media)播放窗口 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] publ

//创建初始化播放器资源 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] extern public static IntPtr libvlc_new(int argc, IntPtr argv); //创建播放器实例 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern IntPtr libvlc_media_player_new(IntPtr libvlc_instance); // 释放libvlc实例 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_release(IntPtr libvlc_instance); //获取库版本信息 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern String libvlc_get_version(); // 从视频来源(例如Url)构建一个libvlc_meida RTSP [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern IntPtr libvlc_media_new_location(IntPtr libvlc_instance, IntPtr path); // 从本地文件路径构建一个libvlc_media rtsp串流不适合调用此接口 // [MarshalAs(UnmanagedType.LPStr)] string path [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern IntPtr libvlc_media_new_path(IntPtr libvlc_instance, IntPtr path); ///

/// 影片长度 ///

/// /// [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern IntPtr libvlc_media_player_get_length(IntPtr libvlc_media_player); //释放对象 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_media_release(IntPtr libvlc_media_inst); // 将视频(libvlc_media)绑定到播放器上 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_media_player_set_media(IntPtr libvlc_media_player, IntPtr libvlc_media); //创建(libvlc_media)播放窗口 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_media_player_new_from_media(IntPtr libvlc_media_player); // 设置图像输出的窗口 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_media_player_set_hwnd(IntPtr libvlc_mediaplayer, Int32 drawable); //播放 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_media_player_play(IntPtr libvlc_mediaplayer); //暂停 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_media_player_pause(IntPtr libvlc_mediaplayer); //停止 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_media_player_stop(IntPtr libvlc_mediaplayer); // 解析视频资源的媒体信息(如时长等) [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_media_parse(IntPtr libvlc_media); // 返回视频的时长(必须先调用libvlc_media_parse之后，该函数才会生效) [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern Int64 libvlc_media_get_duration(IntPtr libvlc_media); // 当前播放的时间 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern Int64 libvlc_media_player_get_time(IntPtr libvlc_mediaplayer); // 设置播放位置(拖动) [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_media_player_set_time(IntPtr libvlc_mediaplayer, Int64 time); ///

/// /// 经典0 /// 完整路径，文件名英文或下划线开头 /// /// /// [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern int libvlc_video_take_snapshot(IntPtr libvlc_mediaplayer, uint num, IntPtr filePath, uint i_width, uint i_height); //media player release [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_media_player_release(IntPtr libvlc_mediaplayer); // 获取音量 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern int libvlc_audio_get_volume(IntPtr libvlc_media_player); //设置音量 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_audio_set_volume(IntPtr libvlc_media_player, int volume); // 设置全屏 [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern void libvlc_set_fullscreen(IntPtr libvlc_media_player, int isFullScreen); ///

///判断是否可以录像 ///

/// /// //Can the media player record the current media? [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern bool libvlc_media_player_is_recordable(IntPtr libvlc_media_player); ///

///判断是否在录像 ///

/// /// [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern bool libvlc_media_player_is_recording(IntPtr libvlc_media_player); ///

/// 录像开始 ///

/// /// 保存路径+文件名（d:\\record (将在D盘根目录保存为record.mp4)） /// [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern int libvlc_media_player_record_start(IntPtr libvlc_media_player, IntPtr psz_PathFilename); ///

/// 录像停止 ///

/// /// [DllImport("libvlc", CallingConvention = CallingConvention.Cdecl)] public static extern int libvlc_media_player_record_stop(IntPtr libvlc_media_player);

本文实例讲述了C#的内存回收方法。分享给大家供大家参考。具体实现方法如下：如下示例代码是调用win32底层操作，可实现内存的回收。代码如下:[DllImport(“kernel32.dll”, EntryPoint = “SetProcessWorkingSetSize”)] public static extern int SetProcessWorkingSetSize(IntPtr process, int minSize, int maxSize); /// /// 释放内存 /// public static void

只有是用Marshal申请的（AllocHGlobal）这种需要释放；对于使用PInvoke返回的IntPtr不用释放；简单来说，这个东西是你创建出来的你就得负责回收，如果是你从别处那里借来用的，一般情况下你不需要负责回收。 https://social.msdn.microsoft.com/Forums/vstudio/zh-CN/da280694-f92c-42e6-afe2-6e126ef35955/-intptr-?forum=2212 ...

C# IntPtr数据类型相关操作byte[]转IntPtr优点缺点IntPtr转Stream参考链接 byte[]转IntPtr //输入buye[]，返回IntPtr IntPtr ArrToPtr(byte[] array) { return System.Runtime.InteropServices.Marshal.UnsafeAddrOfPinnedArrayElement(array, 0); } 优点不使用Marshal创建新的堆，节省内存开销，也避免忘记释放导致的问题缺点看

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