wrapper

postgresql从9.1开始增加了外部表访问的功能，这个功能就是数据库直接读取数据库以外的文件，比如csv或者text等类型的文件，暂时不支持DML。postgresql有各种插件能直连各种异构DB，如oracle_fdw,mysql_fdw,file_fdw等，对数据的迁移是很方便的，这是PG的扩展性较强的一个表现。这里介绍foreign data wrapper的file_fdw使用。 一、环境： OS :CentOS 6.3 DB :PostgreSQL 9.3 二、使用过程 1.创建扩展，因为默认不安装，安装需要手工创建 [postgres@kenyon ~]$ psql psql (9.3.0) Type "help" for help. postgres=# CREATE EXTENSION file_fdw; CREATE EXTENSION postgres=# \dx List of installed extensions Name | Version | Schema | Description ----------+---------+------------+------------------------------------------- file_fdw | 1.0 | public | foreign-data wrapper for

EDIT: OK, OK, I misread. I'm not comparing an int to an Integer. Duly noted. My SCJP book says: When == is used to compare a primitive to a wrapper, the wrapper will be unwrapped and the comparison will be primitive to primitive. So you'd think this code would print true : Integer i1 = 1; //if this were int it'd be correct and behave as the book says. Integer i2 = new Integer(1); System.out.println(i1 == i2); but it prints false . Also, according to my book, this should print true : Integer i1 = 1000; //it does print `true` with i1 = 1000, but not i1 = 1, and one of the answers explained why.

I'm trying to write some wrapper class or function that allows me to execute some code before and after the wrapped function. float foo(int x, float y) { return x * y; } BOOST_PYTHON_MODULE(test) { boost::python::def("foo", <somehow wrap "&foo">); } Ideally, the wrapper should be generic, working for functions and member functions alike, with any signature. More info: I'm looking for a simple way to release/re-acquire the GIL around my expensive C++ calls without having to manually write thin wrappers like this: float foo_wrapper(int x, float y) { Py_BEGIN_ALLOW_THREADS int result = foo(x, y);

I'll go ahead and give a summary to this, how can I use a dialog procedure that is a member of a class? I am creating a window wrapper class, but CreateDialogParam needs a global dialog procedure, so I tried this workaround: I have done a bit of searching on this topic. I am making a Dialog class which I am subclassing to make a CMainWnd and then instantiating that. In the Dialog class I have a member function defined as INT_PTR CALLBACK Dialog::cb_proc(HWND,UINT,WPARAM,LPARAM) . Now, I know that windows must have a global function as a callback procedure. So I made a std::map<HWND,Dialog*>

Is there any open source tool for automatically generating .NET wrappers for a COM DLL library? You can try to use SWIG which is able to generate wrapper code for 18 languages . Also this MSDN article might be useful. There is no wrapper necessary to use a COM object in .NET. In Visual Studio, right-click your project name in the Solution Explorer, and select "Add Reference." Any registered COM objects will be listed in the COM tab. Interop wrappers are only necessary when using .NET assemblies as if they were COM objects - not the other way around as you have described in your question. You