項(xiàng)目管理系統(tǒng)的設(shè)計(jì)與實(shí)現(xiàn)外文翻譯

1、精選優(yōu)質(zhì)文檔-傾情為你奉上畢業(yè)設(shè)計(jì)（論文）外文文獻(xiàn)翻譯（本科學(xué)生用）題 目：_項(xiàng)目管理系統(tǒng)的設(shè)計(jì)與實(shí)現(xiàn)_ _學(xué) 生 姓 名：_ _學(xué)號(hào)：學(xué) 部 （系）: _專 業(yè) 年 級(jí): _指 導(dǎo) 教 師：_ _ 職稱或?qū)W位： 2010 年 2 月 15 日 外文文獻(xiàn)翻譯：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.) 動(dòng)態(tài)鏈接庫(kù)的基本知識(shí)Windows應(yīng)用程序是一個(gè)可執(zhí)行文件，它通常建立一個(gè)或幾個(gè)窗口，并使用消息循環(huán)接收使用者輸入。通常，動(dòng)態(tài)鏈接庫(kù)并不能直接執(zhí)行，也不接收消息。它們是一些獨(dú)立的文件，其中包含能被程序或其它DLL呼叫來(lái)完成一定作業(yè)的函數(shù)。只有在其它模塊呼叫動(dòng)態(tài)鏈接庫(kù)中的函數(shù)時(shí)，它才發(fā)揮作用。所謂動(dòng)態(tài)鏈接，是指Windows把一個(gè)模塊中的函數(shù)呼叫連結(jié)到

21、動(dòng)態(tài)鏈接庫(kù)模塊中的實(shí)際函數(shù)上的程序。在程序開(kāi)發(fā)中，您將各種目標(biāo)模塊(.OBJ)、執(zhí)行時(shí)期鏈接庫(kù)(.LIB)文件，以及經(jīng)常是已編譯的資源(.RES)文件連結(jié)在一起，以便建立Windows的.EXE文件，這時(shí)的連結(jié)是靜態(tài)連結(jié)。動(dòng)態(tài)鏈接與此不同，它發(fā)生在執(zhí)行時(shí)期。KERNEL32.DLL、USER32.DLL和GDI32.DLL、各種驅(qū)動(dòng)程序文件如KEYBOARD.DRV、SYSTEM.DRV和MOUSE.DRV和視訊及打印機(jī)驅(qū)動(dòng)程序都是動(dòng)態(tài)鏈接庫(kù)。這些動(dòng)態(tài)鏈接庫(kù)能被所有Windows應(yīng)用程序使用。有些動(dòng)態(tài)鏈接庫(kù)（如字體文件等）被稱為純資源。它們只包含數(shù)據(jù)（通常是資源的形式）而不包含程序代碼。由此可

22、見(jiàn)，動(dòng)態(tài)鏈接庫(kù)的目的之一就是提供能被許多不同的應(yīng)用程序所使用的函數(shù)和資源。在一般的操作系統(tǒng)中，只有操作系統(tǒng)本身才包含其它應(yīng)用程序能夠呼叫來(lái)完成某一作業(yè)的例程。在Windows中，一個(gè)模塊呼叫另一個(gè)模塊函數(shù)的程序被推廣了。結(jié)果使得編寫(xiě)一個(gè)動(dòng)態(tài)鏈接庫(kù)，也就是在擴(kuò)充Windows。當(dāng)然，也可認(rèn)為動(dòng)態(tài)鏈接庫(kù)（包括構(gòu)成Windows的那些動(dòng)態(tài)鏈接庫(kù)例程）是對(duì)使用者程序的擴(kuò)充。盡管一個(gè)動(dòng)態(tài)鏈接庫(kù)模塊可能有其它擴(kuò)展名（如.EXE或.FON），但標(biāo)準(zhǔn)擴(kuò)展名是.DLL。只有帶.DLL擴(kuò)展名的動(dòng)態(tài)鏈接庫(kù)才能被Windows自動(dòng)加載。如果文件有其它擴(kuò)展名，則程序必須另外使用LoadLibrary或者LoadLibr

23、aryEx函數(shù)加載該模塊。您通常會(huì)發(fā)現(xiàn)，動(dòng)態(tài)鏈接庫(kù)在大型應(yīng)用程序中最有意義。例如，假設(shè)要為Windows編寫(xiě)一個(gè)由幾個(gè)不同的程序組成的大型財(cái)務(wù)軟件包，就會(huì)發(fā)現(xiàn)這些應(yīng)用程序會(huì)使用許多共同的例程?？梢园堰@些公共例程放入一個(gè)一般性的目的碼鏈接庫(kù)（帶.LIB擴(kuò)展名）中，并在使用LINK靜態(tài)連結(jié)時(shí)把它們加入各程序模塊中。但這種方法是很浪費(fèi)的，因?yàn)檐浖械拿總€(gè)程序都包含與公共例程相同的程序代碼。而且，如果修改了鏈接庫(kù)中的某個(gè)例程，就要重新連結(jié)使用此例程的所有程序。然而，如果把這些公共例程放到稱為ACCOUNT.DLL的動(dòng)態(tài)鏈接庫(kù)中，就可解決這兩個(gè)問(wèn)題。只有動(dòng)態(tài)鏈接庫(kù)模塊才包含所有程序都要用到的例程。這樣能為儲(chǔ)存文件節(jié)省磁盤(pán)空間，并且在同時(shí)執(zhí)行多個(gè)應(yīng)用程序時(shí)節(jié)省內(nèi)存，而且，可以修改動(dòng)態(tài)鏈接庫(kù)模塊而不用重新連結(jié)各個(gè)程序。動(dòng)態(tài)鏈接庫(kù)實(shí)際上是可以獨(dú)立存在的。例如，假設(shè)您編寫(xiě)了一系列3D繪圖例程，并把它們放入名為GDI3.DLL的DLL中。如果其它軟件開(kāi)發(fā)者對(duì)此鏈接庫(kù)很感興趣，您就可以授權(quán)他們將其加入他們的圖形程序中。使用多個(gè)這樣的圖形程序的使用者只需要一個(gè)GDI3.DLL文件。鏈接庫(kù)：一詞多義動(dòng)態(tài)鏈接庫(kù)有著令人困惑的印象，部分原因是由于鏈接