wrapper | 易学教程

Access webcam from multiple applications simultaneously

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问题 The problem background - there are two different windows applications that are trying to access webcam on the computer at the same time. Currently, only one application is able to access to it. I want to be able to allow both applications to simultaneously access the webcam. A common example of my problem is, skype and yahoo messenger trying to access the webcam on the computer at the same time. I found a few softwares (manycam.com, http://www.splitcamera.com/) that allow this on windows. But

Setting an Item in nested dictionary with setitem

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问题 Here's what I did, trying to create a wrapper for a dict-like database, among other functions: class database(object): def __init__(self, name): self.name = name self.db = anydbm.open(name, 'c') def __getitem__(self, key): key = str(key) try: self.db = anydbm.open(self.name, 'w') except Exception,e: raise e else: return cPickle.loads(self.db[key]) finally: self.db.close() def __setitem__(self, key, value): key = str(key) value = cPickle.dumps(value) try: self.db = anydbm.open(self.name, 'w')

Non-type template parameter… that's a template! (C++)

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问题 I'm basically looking to generate a wrapper for a generic C function without having to manually specify the types. So I have a callback with a fixed prototype but I'm going to need to do some special code in the wrapper based on the type of the wrapped function... So basically I'm thinking about using a static method in a class template to wrap my function to a conforming interface e.g.: // this is what we want the wrapped function to look like typedef void (*callback)(int); void foobar(

php - unset $this

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问题 I've made a class that acts like an file wrapper. When user call delete method, i want to unset the object (actually $this). Is there a way (workaround) to do that? The manual said no, there is no way... 回答1: As far as I know, there is no way to destroy a class instance from within the class itself. You'll have to unset the instance within its scope. $myClass = new fooBar(); unset($myClass); Somewhat related: Doing the above will automatically call any existing __destruct() magic method of

What is the best way to call into Swift from C?

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问题 Calling into C from Swift is pretty simple, however I'm looking into making a bi-directional wrapper in C, so my C has to call Swift functions. Right now, I can do this by declaring function pointers in C, and having my C functions call them after the Swift side has set them up to call code in Swift. My C header file: typedef void (*callback_t)(void); void callBackIntoSwift( callback_t cb ); My C implementation file: #include "stuff.h" #include <stdio.h> void callBackIntoSwift( callback_t cb

如何使用首选的差异工具/查看器查看“ git diff”输出？

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【推荐】2019 Java 开发者跳槽指南.pdf(吐血整理) >>> 当我输入 git diff ，我想使用我选择的可视化diff工具（在Windows上为SourceGear“ diffmerge”）查看输出。如何配置git来做到这一点？ #1楼使用新的git difftool ，就像将它添加到 .gitconfig 文件中一样简单： [diff] tool = any-name [difftool "any-name"] cmd = "\"C:/path/to/my/ext/diff.exe\" \"$LOCAL\" \"$REMOTE\"" （可选）还添加： [difftool] prompt = false 还要查看 diffall ，这是我编写的一个简单脚本，用于扩展烦人的（IMO）默认情况下以串行方式打开每个文件的diff行为。 Windows上的全局.gitconfig位于 %USERPROFILE%\\.gitconfig #2楼对于如何在1.6.3之前的git版本上配置diff工具的linux版本（1.6.3在git中添加了difftool），这是一个非常简洁的教程，简单来说：步骤1：将其添加到您的.gitconfig [diff] external = git_diff_wrapper [pager] diff = 第2步：创建一个名为git

SQLite3 in C#.NET

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问题 I'm trying to use SQLite3 in C#.NET. I've googled around and found some different API's. I also checked SQLite's website for wrappers. I like them, but want to write my own wrapper without using an added dependency. All wrappers I find that don't require an added dependency aren't free. I'm wondering how one would read from, execute, and write to a sqlite3 database. Is it a socket connection(tcp? udp? etc?)? I've tried searching this answer on google and all I get are library-specific answers

Is there a C header parser tool for wrapper generation like gccxml?

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问题 I need to write a few c header wrappers for a new programming language and would like something like gccxml but without the full dependency on gcc and the problems it gives on a windows system. Just needs to read C not C++. Output in any format is okay as long it is fully documented. Need it for Curl, SQLite, GTK2, SDL, OpenGL, Win32 API and C posix API's on Linux/Solaris/FreeBSD/MacOSX. 回答1: VivaCore is very cool. Have you tried SWIG the wikipedia page on ffi has some good links too. I think

c++11: Templated wrapper function

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问题 I try to create a general wrapper function which takes any function as argument and also their parameters. Just something like the std::thread constructor. My current code is: #include <iostream> using namespace std; template<typename FUNCTION, typename... ARGS> void wrapper(FUNCTION&& func, ARGS&&... args) { cout << "WRAPPER: BEFORE" << endl; auto res = func(args...); cout << "WRAPPER: AFTER" << endl; //return res; } int dummy(int a, int b) { cout << a << '+' << b << '=' << (a + b) << endl;

What does boost::thread sleep() do?

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问题 I am currently working on a small wrapper class for boost thread but I dont really get how the sleep function works, this is what I have got so far: BaseThread::BaseThread(){ thread = boost::thread(); bIsActive = true; } BaseThread::~BaseThread(){ join(); } void BaseThread::join(){ thread.join(); } void BaseThread::sleep(uint32 _msecs){ if(bIsActive) boost::this_thread::sleep(boost::posix_time::milliseconds(_msecs)); } This is how I implemented it so far but I dont really understand how the