Compiling and Running an Application from the Command Line

Transcription

1 Appendix A Compiling and Running an Application from the Command Line This appendix describes how to run applications at the command line without using the integrated development environment (IDE) of Visual Studio. To begin, you can download Microsoft s.net Framework 2.0 Software Development Kit (SDK) from the Microsoft Web site as a free download.at the time of writing, the URL for the download was size of the download is approximately 350 MB. It can be used on Windows Vista,Windows 2000,Windows XP, and later versions of Windows operating systems.the SDK includes the extensive library of.net classes, C# compiler, common language runtime, documentation, samples, and everything you need to write, build, test, and deploy applications. COMMAND-LINE EXECUTION You can type your source code statements into a simple editor, such as Notepad. To start, navigate to the directory where you store your programming work. In the editor, select the Save As option from the File menu when you are ready to save the source code file.when you save the file, use the same name as the class name for the filename identifier. In addition, add a dot following the file identifier name and an extension of cs onto the end of the filename. Figure A-1 illustrates saving your work from within Notepad. 925

2 926 Appendix A Compiling and Running an Application from the Command Line Figure A-1 Saving the Notepad file with a.cs extension Notice in Figure A-1 that the name of the class is FirstProgram; thus, the name of the file should be FirstProgram.cs. When you save the text file, do not use the.txt extension as part of the filename.to avoid having the.txt extension automatically added by the editor, you can either enclose the entire name, including extension, in double quotes (" "), as FirstProgram.cs or select All Files from the Save as type selection, as illustrated in Figure A-1. Compiling the Source Code from the DOS Command Prompt Open a command window to compile and execute your application by selecting: Start, Run. Type cmd, as shown in Figure A-2.This opens a DOS window with a command prompt.

3 Command-Line Execution 927 A Figure A-2 Opening a cmd window N O TE A command window can also be opened by typing the word command. However, issues related to long filenames are easier to deal with if you open the command window with cmd instead of command. At the cmd prompt, you move into the directory in which you stored your source code file by typing cd (change directory) followed by the full path of the directory. If you created a directory named CSharpProjects on your local hard drive and placed it at the root level, you would type cd C:\ CSharpProjects, as shown in Figure A-3. Figure A-3 Moving into the folder used to store your projects Start the compiler from the cmd line by entering the compiler s program name: csc. Submit the source code file to the compiler by entering its filename on the command line, as in the following: csc filename.cs

4 928 Appendix A Compiling and Running an Application from the Command Line To compile the source code file named FirstProgram, type the following: csc FirstProgram.cs N O TE Be sure to type the.cs extension. Otherwise, you receive a source file not found error. Receiving the error message shown in Figure A-4 indicates that csc is not recognized as an internal or external command, operable program, or batch file, and the operating system is not able to locate the csc.exe file.you need to indicate where the operating system can find the csc.exe file. When you loaded the.net SDK or Visual Studio, the environment variables for the path might not have been set. Figure A-4 Error message indicating complier cannot be found If you have Visual Studio loaded, but want to run your application from the command prompt, you can skip to the section titled, Compiling Program Statements from the Visual Studio Command Prompt. Setting the Path to the Compiler (csc) First, you need to locate the compilation program, csc.exe, on your system.this can be done using the Search feature on your computer (either from the Start menu, My Computer Icon, or Windows Explorer). Search for the file named csc.exe. Be sure to include System Folders in the search. If you are using Windows XP, you can select the Search System Folders option by expanding the More Advanced options feature. On the system used to write this book, Version 2.0 is located at C:\WINDOWS\Microsoft.NET\Framework\v After you locate the csc.exe, you compile from the cmd prompt by typing the full path to the csc.exe file (C:\WINDOWS\Microsoft.NET\Framework\v \csc.exe).What a pain! Obviously, you don t want to type the full path to compile your code. Another approach is to issue a path command.to do this at the cmd prompt, type path = followed

5 Command-Line Execution 929 by the full path beginning at C:\. For example, on the system used for this book, because csc.exe was found at C:\WINDOWS\Microsoft.NET\Framework\v , you would type: path = C:\WINDOWS\Microsoft.NET\Framework\v This sets the path for this cmd session only. If you close the cmd prompt window, you have to reissue the path command the next time you run the compiler (and each time you want to run csc). A Changing the System Path Settings A better approach for setting the path is to use System Properties to make a one-time change to the path. This establishes the path from then on. These changes can be made only when using an Administrator login. If you are using a classroom or lab computer, have an instructor help you with this change. For your home systems, the path can be changed by selecting the following: Start, Control Panel, System, Advanced tab, Environmental Variables, System Variables, Path, Edit N O TE These steps are specific to the Windows XP operating system. If you are running Windows 2000, you must click Settings before clicking Control Panel. You should add the path to csc.exe onto the end of the list. Do not simply replace the values found in the Path variable. If you do, some of your other programs might not function properly. Begin by typing a semicolon (;) and follow that with the full path starting at C:\. Figure A-5 illustrates typing a new path string onto the end of the list. Notice the figure shows the semicolon being typed as the separator between what was previously stored in the path s variable value and the new entry that is being typed.the full path string to be typed is shown here. ;C:\Windows\Microsoft.Net\Framework\v

6 930 Appendix A Compiling and Running an Application from the Command Line Figure A-5 Adding the path to the environment variables N O TE On your personal computer system, the path string you add onto the end of the list might be slightly different from that shown in Figure A-5. The typed value must match the location where csc.exe is stored on your system. Remember the path can be found using the Search feature of the operating system. After you add this path to the existing environment variables, you do not have to type the path command again. If you do not have Visual Studio installed, this setting is saved and is definitely the preferred method for setting up your system to use the SDK. As shown in Figure A-6, after the path is set, you no longer receive an error message indicating the csc program is not recognized. FirstProgram.cs was compiled twice.when it was first compiled, a semicolon was removed.the last compilation shows the output when no errors are present.

7 Command-Line Execution 931 A Figure A-6 Compiling FirstProgram.cs Compiling Program Statements from the Visual Studio Command Prompt If you have Visual Studio installed, but decide not to use the IDE, a better alternative for command-line compilation and execution is to use the Visual Studio command-line tools. You could still create the source code using a simple editor such as Notepad.When you are ready to compile, do not open a DOS command window from the Start, RUN option. Instead, use one of the Visual Studio tools.this approach offers the advantage of not having to deal with setting any path commands. When you install Visual Studio, the installation includes a tool, which enables you to open a command window with the correct environment variables already set. As shown in Figure A-7, you can open the Visual Studio 2005 command prompt by selecting the following menu items in this order: Start, All Programs, Microsoft Visual Studio 2005, Visual Studio Tools, Visual Studio 2005 Command Prompt

8 932 Appendix A Compiling and Running an Application from the Command Line Figure A-7 Opening a command window using the Visual Studio Command Prompt tool Navigate to the directory in which you stored the source code file. If you created a directory named CSharpProjects, you type cd C:\ CsharpProjects, as shown in Figure A-4.You start the compiler from the command line just as previously presented. Type the program name for the compiler csc.then pass in your source code file by entering the filename on the command line, as in the following: csc FirstProgram.cs As noted before, be sure to include the.cs file extension. If you get syntax error messages, go back to the simple editor and modify the source code.after you save the source code, you can try compiling again.when you receive no errors, you are ready to move to the next step. Executing the Application from the Command Prompt When there are no syntax errors, a new file is created.this file has the same name as the source code file with one exception: Instead of having the source code extension of.cs, the object file has an.exe extension. After you create the object file, you might want to use My Computer or Windows Explorer to confirm that you actually created the new file. Move to the directory containing the file, just as you do when compiling, and type the name of the file. It is not necessary to type the.exe extension. Simply type the filename identifier without any file extension, as follows: filename For example, to see the results of the FirstProgram application from the command line, execute the application by typing at the command prompt the name of the file, without any file extension.to run the FirstProgram application, you type: FirstProgram

9 Compiling and Running an Application from the Command Line 933 Compiler Options You can use several options when compiling with a command line. Some programmers use the command line because of the flexibility of its options. Table A-1 includes some of the more commonly used compiler options. A Table A-1 Compiler Option C# command-line compiler options Description /? Lists all compiler options with a brief description of each one /doc /help /main /out /target:exe /target:library /target:winexe Produces an XML document containing the XML comments Displays a listing of all compiler options with a brief description of each one Specifies the name of the file (and location) containing the main method Specifies the name of the output (.exe) file when it should differ from the original source name Causes the output to be an executable console application Causes the output to be a library file (.dll) Causes the output to be an executable Windows application Each of these options would be added to the command-line compilation statement. To compile, you type csc followed by the source code filename. Thus, to compile a file named testfile.cs and produce a.dll named testfile.dll, you would type the following at the command line: csc /target:library testfile.cs Other Platforms A number of third-party vendors create C# compilers. Some do not even have to be run on a Windows-based platform. If you develop on a Linux platform, you might consider downloading Mono ( are encouraged to search the Internet to locate new compilers that might be developed after this book is printed.

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