项目管理系统的设计与实现外文翻译

1、精选优质文档-倾情为你奉上毕业设计（论文）外文文献翻译（本科学生用）题 目：_项目管理系统的设计与实现_ _学 生 姓 名：_ _学号：学 部 （系）: _专 业 年 级: _指 导 教 师：_ _ 职称或学位： 2010 年 2 月 15 日 外文文献翻译：Library BasicsA Windows program is an executable file that generally creates one or more windows and uses a message loop to receive user input. Dynamic-link libraries are

2、 generally not directly executable, and they generally do not receive messages. They are separate files containing functions that can be called by programs and other DLLs to perform certain jobs. A dynamic-link library is brought into action only when another module calls one of the functions in the

3、 library. The term "dynamic linking" refers to the process that Windows uses to link a function call in one module to the actual function in the library module. "Static linking" occurs during program development when you link various object (.OBJ) modules, run-time library (.LIB)

4、 files, and usually a compiled resource (.RES) file to create a Windows .EXE file. Dynamic linking instead occurs at run time. KERNEL32.DLL, USER32.DLL, and GDI32.DLL; the various driver files such as KEYBOARD.DRV, SYSTEM.DRV, and MOUSE.DRV; and the video and printer drivers are all dynamic-link lib

5、raries. These are libraries that all Windows programs can use. Some dynamic-link libraries (such as font files) are termed "resource-only." They contain only data (usually in the form of resources) and no code. Thus, one purpose of dynamic-link libraries is to provide functions and resourc

6、es that can be used by many different programs. In a conventional operating system, only the operating system itself contains routines that other programs can call on to do a job. In Windows, the process of one module calling a function in another module is generalized. In effect, by writing a dynam

7、ic-link library, you are writing an extension to Windows. Or you can think of DLLs, including those that make up Windows, as extensions to your program. Although a dynamic-link library module can have any extension (such as .EXE or .FON), the standard extension is .DLL. Only dynamic-link libraries w

8、ith the extension .DLL will be loaded automatically by Windows. If the file has another extension, the program must explicitly load the module by using the LoadLibrary or LoadLibraryEx function. You'll generally find that dynamic libraries make most sense in the context of a large application. F

9、or instance, suppose you write a large accounting package for Windows that consists of several different programs. You'll probably find that these programs use many common routines. You could put these common routines in a normal object library (with the extension .LIB) and add them to each of t

10、he program modules during static linking with LINK. But this approach is wasteful, because each of the programs in this package contains identical code for the common routines. Moreover, if you change one of the routines in this library, you'll have to relink all the programs that use the change

11、d routine. If, however, you put these common routines in a dynamic-link library called, for instance, ACCOUNT.DLL, you've solved both problems. Only the library module need contain the routines required by all the programs, thus requiring less disk space for the files and less memory space when

12、running two or more of the applications simultaneously, and you can make changes to the library module without relinking any of the individual programs. Dynamic-link libraries can themselves be viable products. For instance, suppose you write a collection of three-dimensional drawing routines and pu

13、t them in a DLL called GDI3.DLL. If you then interest other software developers in using your library, you can license it to be included with their graphics programs. A user who has several of these programs would need only one GDI3.DLL file. Library: One Word, Many MeaningsPart of the confusion sur

14、rounding dynamic-link libraries results from the appearance of the word "library" in several different contexts. Besides dynamic-link libraries, we'll also be talking about "object libraries" and "import libraries." An object library is a file with the extension .LI

15、B containing code that is added to your program's .EXE file in the process called static linking when you run the linker. For example, in Microsoft Visual C+, the normal C run-time object library that you link with your program is called LIBC.LIB. An import library is a special form of an object

16、 library file. Like object libraries, import libraries have the extension .LIB and are used by the linker to resolve function calls in your source code. However, import libraries contain no code. Instead, they provide the linker with information necessary to set up relocation tables within the .EXE

17、file for dynamic linking. The KERNEL32.LIB, USER32.LIB, and GDI32.LIB files included with the Microsoft compiler are import libraries for Windows functions. If you call the Rectangle function in a program, GDI32.LIB tells LINK that this function is in the GDI32.DLL dynamic-link library. This informa

18、tion goes into the .EXE file so that Windows can perform dynamic linking with the GDI32.DLL dynamic-link library when your program is executed. Object libraries and import libraries are used only during program development. Dynamic-link libraries are used during run time. A dynamic library must be p

19、resent on the disk when a program is run that uses the library. When Windows needs to load a DLL module before running a program that requires it, the library file must be stored in the directory containing the .EXE program, the current directory, the Windows system directory, the Windows directory,

20、 or a directory accessible through the PATH string in the MS-DOS environment. (The directories are searched in that order.) 动态链接库的基本知识Windows应用程序是一个可执行文件，它通常建立一个或几个窗口，并使用消息循环接收使用者输入。通常，动态链接库并不能直接执行，也不接收消息。它们是一些独立的文件，其中包含能被程序或其它DLL呼叫来完成一定作业的函数。只有在其它模块呼叫动态链接库中的函数时，它才发挥作用。所谓动态链接，是指Windows把一个模块中的函数呼叫连结到

21、动态链接库模块中的实际函数上的程序。在程序开发中，您将各种目标模块(.OBJ)、执行时期链接库(.LIB)文件，以及经常是已编译的资源(.RES)文件连结在一起，以便建立Windows的.EXE文件，这时的连结是静态连结。动态链接与此不同，它发生在执行时期。KERNEL32.DLL、USER32.DLL和GDI32.DLL、各种驱动程序文件如KEYBOARD.DRV、SYSTEM.DRV和MOUSE.DRV和视讯及打印机驱动程序都是动态链接库。这些动态链接库能被所有Windows应用程序使用。有些动态链接库（如字体文件等）被称为纯资源。它们只包含数据（通常是资源的形式）而不包含程序代码。由此可

22、见，动态链接库的目的之一就是提供能被许多不同的应用程序所使用的函数和资源。在一般的操作系统中，只有操作系统本身才包含其它应用程序能够呼叫来完成某一作业的例程。在Windows中，一个模块呼叫另一个模块函数的程序被推广了。结果使得编写一个动态链接库，也就是在扩充Windows。当然，也可认为动态链接库（包括构成Windows的那些动态链接库例程）是对使用者程序的扩充。尽管一个动态链接库模块可能有其它扩展名（如.EXE或.FON），但标准扩展名是.DLL。只有带.DLL扩展名的动态链接库才能被Windows自动加载。如果文件有其它扩展名，则程序必须另外使用LoadLibrary或者LoadLibr

23、aryEx函数加载该模块。您通常会发现，动态链接库在大型应用程序中最有意义。例如，假设要为Windows编写一个由几个不同的程序组成的大型财务软件包，就会发现这些应用程序会使用许多共同的例程。可以把这些公共例程放入一个一般性的目的码链接库（带.LIB扩展名）中，并在使用LINK静态连结时把它们加入各程序模块中。但这种方法是很浪费的，因为软件包中的每个程序都包含与公共例程相同的程序代码。而且，如果修改了链接库中的某个例程，就要重新连结使用此例程的所有程序。然而，如果把这些公共例程放到称为ACCOUNT.DLL的动态链接库中，就可解决这两个问题。只有动态链接库模块才包含所有程序都要用到的例程。这样能为储存文件节省磁盘空间，并且在同时执行多个应用程序时节省内存，而且，可以修改动态链接库模块而不用重新连结各个程序。动态链接库实际上是可以独立存在的。例如，假设您编写了一系列3D绘图例程，并把它们放入名为GDI3.DLL的DLL中。如果其它软件开发者对此链接库很感兴趣，您就可以授权他们将其加入他们的图形程序中。使用多个这样的图形程序的使用者只需要一个GDI3.DLL文件。链接库：一词多义动态链接库有着令人困惑的印象，部分原因是由于链接