HOWTO: Make VC++ Recognize File Extensions as C/C++ Files

• Microsoft Visual Studio versions 97, 97sp1, 97sp2, 97sp3
• Microsoft Visual C++, 32-bit Editions, versions 4.0, 4.0a, 4.1, 4.2, 4.2b, 5.0, 5.0sp1, 5.0sp2, 5.0sp3

SUMMARY

Microsoft's Visual C++ Integrated Development Environment (IDE) recognizes the following file extensions as C++ source files: .c, .cpp, and .cxx. In some cases, a programmer may want to use other file extensions for C++ files; for example, Unix C++ source files often use the .cc extension.

Using the steps in this article, source files with other file extensions may benefit from the Visual C++ IDE's syntax coloring, automatic indentation, and other usage enhancements. This article describes how to automatically compile such files as C/C++ and associate the C++ icon with these files in Windows Explorer.

MORE INFORMATION

The following procedure causes the Visual C++ IDE to recognize extensions other than .c, .cpp, and .cxx as a C/C++ source file. These changes involve altering registry settings.

WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

Microsoft STRONGLY recommends saving the current registry settings before starting this procedure. For additional information, please see the following articles in the Microsoft Knowledge Base (the second link applies to Windows 95 as well):

   ARTICLE-ID: Q103280
   TITLE     : Using an Emergency Repair Disk Created by Windows NT

   ARTICLE-ID: Q164931
   TITLE     : Using Regedit to Backup Your Windows NT Registry

1. Close any running instances of Developer Studio.

2. On the Start menu, click Run.

3. Type "regedit" (without the quotation marks) and click OK to start the Registry Editor.

1. Right-click HKEY_CLASSES_ROOT and select New | Key.

2. A key name will appear; change "New Key #1" to ".cc" (the period is mandatory).

3. Click the new .cc key, then double-click Default in the right-hand pane of the Registry Editor.

4. In the Value Data field, type "cppfile" (without the quotation marks). Click OK.

The following steps apply to keys and values located on the home key. In the Registry Editor, locate the user settings home key for Developer Studio. For various versions, the home key is:

   5.0 (which ships with Visual Studio 97)
      HKEY_CURRENT_USER\Software\Microsoft\DevStudio\5.0\
   4.x
      HKEY_CURRENT_USER\Software\Microsoft\Developer

1. Locate the following keys under Build System\Components\Platforms:

         Win32(ALPHA)\Tools\C/C++ Compiler for Alpha
         Win32(PowerPC)\Tools\C/C++ Compiler for PowerPC
         Win32(x86)\Tools\C/C++ Compiler for 80x86
   

   If WinCE 2.0 is installed, the following keys will also be present:

         Win32(WCE x86em)\Tools\C++ Compiler for 80x86em (Emulation)
         Win32(WCE MIPS)\Tools\C/C++ Compiler Mips R4100
         Win32(WCE SH)\Tools\C/C++ Compiler for SH
   

2. Each of those keys has a setting called "Input_Spec". Double-click "Input_Spec"; then, in the Value Data field, add ";*.cc" to the end of the existing list of extensions. Click OK.

1. Locate the key Text Editor\Tabs/Language Settings\C/C++.

2. Double-click the "FileExtensions" setting; add ";cc" to the end of the existing list of extensions. Click OK.

3. Close the Registry Editor.

4. Start Developer Studio and create a new file or open an existing one with the extension(s) just added. Syntax coloring and automatic indentation should be in effect.

Although the IDE starts the C/C++ compiler tool for the file extensions added in the steps above, the compiler needs to know whether to compile the file as C or C++. The compiler normally compiles .c files as C, and compiles .cpp and .cxx as C++. For all other extensions, the compiler needs an explicit parameter: /TC compiles files as C, /TP compiles files as C++. Each project that includes files with custom extensions needs an explicit /TC or /TP parameter. The following steps illustrate how to do this:

1. Open a project in Developer Studio.

2. Click Settings on the Project menu.

3. In the resulting dialog box, select the configuration and project.

4. Click the C/C++ tab.

5. In the Project Options text box at the bottom, add /TP or /TC to the end of the listed options. Click OK.

If necessary, a custom build step can launch the C/C++ compiler (CL.EXE) with settings specific to a single file. This is less desirable, because the custom build step requires explicitly listing all of the compiler options. See REFERENCES for online documentation of instructions on adding a custom build step.

REFERENCES

Visual C++ Programmer's Guide, Compiling and Linking, Details, Compiler Reference.

Visual C++, Developer Studio Environment User's Guide, Working With Projects, How Do I... Topics: Working With Projects, Customizing a Build Process.