With Apple now shipping Intel-based Macintoshes, the remaining software developers still using the CodeWarrior Integrated Development Environment (IDE) have realized it's time to move their applications to the Xcode IDE. The reason is simple: by moving existing CodeWarrior applications to Apple's Xcode, they can create universal binaries—applications that include executable code that runs on both PowerPC and Intel-based Macintosh computers. Developers using Xcode are able to compile their applications to work on Intel-based as well as PowerPC-based Macs.

If you currently use CodeWarrior, you will find that porting your application to Xcode opens up new opportunities while providing a sophisticated development environment that is comfortable to use, and relatively easy to learn. This article can help you get started: it looks at some of the top-level issues involved, offers some guidance on how to proceed, and discusses some issues that you may encounter when you begin the process. It can help you as a CodeWarrior developer understand what you need to know so that you can move your C/C++/Objective-C application to Xcode quickly and without disruption to your work flow.

Similarities and Differences

CodeWarrior and Xcode are both high quality, feature-rich IDEs that allow you to build solid, high-performance Mac OS X applications. Although the tools differ slightly in their details, the key concepts remain the same. Both Xcode and CodeWarrior include an editor, compiler, linker, and debugger. Both allow you to manage projects using a Graphical User Interface (GUI) that groups source code files, resource files, and existing libraries into logical groups for inclusion in the finished product.

There are some key differences between CodeWarrior and Xcode, both on the surface and down in the internals, and the degree to which they affect your application and how easily it builds will depend on several factors. In some cases, and depending on your application's complexity, the differences may not affect you directly. For example, Xcode uses the open source GNU Compiler Collection (GCC) 4 under the hood to build and link applications. In contrast, CodeWarrior includes a custom compiler, which has its own strengths, weaknesses and differences. If you use compiler-specific directives in your CodeWarrior project, you may need to replace or remove those directives. You may also have some tweaking to do because GCC 4 is more standards-compliant than CodeWarrior, and may flag issues in your code that the CodeWarrior compiler passes over.

Access/Search Paths

Project management details differ somewhat. For example, CodeWarrior allows separate User and System Access Paths, allowing you to include files from one or more locations using both relative and absolute search paths, as shown in Figure 1.

Figure 1: CodeWarrior Project Access Paths

Xcode includes Access Paths (called Search Paths) and expands on the concept by offering separate Header, User Header, Library, and Framework Search Paths, which can also be specified as absolute or relative paths, as shown in Figure 2.

Figure 2: Xcode Project Search Paths

Source Trees

CodeWarrior source trees allow you to assign an alias to a path, and then include the alias in the target Access Path. Figure 3 shows a target-specific source tree definition in CodeWarrior.

Figure 3: CodeWarrior Project Source Tree Setting

Xcode also supports source trees through the Xcode Preferences dialog. Source trees in Xcode are global in scope, meaning they may be used across all projects. The entry shown in Figure 4 is the actual path to the CodeWarrior folder, and was created automatically by the project importer.

Figure 4: Xcode Source Tree Preference

After you define the Source Tree alias in the application preferences, it is available for use in the project target settings.

Build Configurations

You will find additional Xcode features that make development easier, such as build configurations. Xcode build configurations provide flexibility in managing multiple configurations for each build target. With CodeWarrior, each target has only one configuration, which is specified in its build settings: if you want to vary the build you need to create a new target. But with Xcode, each target can have multiple configurations build settings, allowing you to define more than one way to build, for example, the Debug target. While you are exploring the potential of build configurations, you can still reap the benefits because when you import a CodeWarrior project, Xcode automatically creates a build configuration named "Imported CodeWarrior Settings" for each target, and uses that as the default, as shown in Figure 5.

Figure 5: The Default Build Configuration for an Imported Project

Fix and Continue

Both IDEs include interactive debuggers, but the Xcode debugger includes the unique Fix and Continue feature, which allows you to make a code change while the application is paused in the debugger, recompile that file, and restart debugging from the point where you paused.

The similarities between Code Warrior and Xcode are numerous, and Xcode's additional features will help you quickly become productive while you get familiar with the differences between the two IDEs.

Import Into Xcode

The first step in importing a CodeWarrior project into Xcode is to prepare the project while in CodeWarrior. If you have not already done so, convert the CodeWarrior application to Mac OS X and Mach-O before moving it to Xcode. Since Mach-O is the only binary format supported on Mac OS X, you should make sure that the Mach-O version of your CodeWarrior project builds and runs. This will reduce the number of headaches and build errors you experience during and after importing, when you are trying to deal with build errors in a new IDE.

You should clean up the CodeWarrior project by removing unused targets (e.g., Windows) and files. Any source trees defined in project settings should be moved to the CodeWarrior application preferences, and removed from the project settings, because the importer can import global source trees: there is an Import Global Source Trees checkbox in the importer dialog that controls this behavior, as shown in Figure 6. The importer ignores project-specific source trees.

Figure 6: The Import Global Source Trees Checkbox

The second step is to import the project into Xcode. To assist you, Xcode includes an importer (under File > Import Project...) that can specifically import CodeWarrior projects. It creates an Xcode project structure and converts many project settings to their Xcode equivalents, reducing the amount of rework you need to perform. However, the importer is not foolproof, so you will likely have some post-import work to do.

One tool that can help you tremendously during the import is /Applications/Utilities/Console.app. The Console displays errors encountered during the import process (see Listing 1), so you should check it while or after the importer executes. The details in the Console messages may allow you to resolve many import problems.

Listing 1: Importer Error Messages Logged In The Console

2005-10-27 13:26:35.685 Xcode[217] Couldn't find file "crt1.o" for addition to target                        \
                                                                        "Toolbox Mach-O Debug"... skipping
2005-10-27 13:26:35.691 Xcode[217] Couldn't find file "MSL_All_Mach-O_D.lib" for addition to target          \
                                                                        "Toolbox Mach-O Debug"... skipping
2005-10-27 13:26:37.177 Xcode[217] Info.plist file for target 'Toolbox Mach-O Debug' not generated for the   \
                                                                                       following reason: {
    NSAppleScriptErrorBriefMessage = "File CodeWarrior:CarbonApp:::SimpleHello Debug.app:Contents:Info.plist \
                                                                                       wasn't found."; 
    NSAppleScriptErrorMessage = "File CodeWarrior:CarbonApp:::SimpleHello Debug.app:Contents:Info.plist      \
                                                                                       wasn't found."; 
    NSAppleScriptErrorNumber = -43; 
    NSAppleScriptErrorRange = <00000000 00000000 >; 
}

After importing the project into Xcode, try building your project. Building in Xcode is similar to the make process in CodeWarrior, and a preprocessor, compiler, and linker are all included. If the build is not successful, then you may need to resolve import problems with header files, libraries, symbols, or non-compliant code.

Application-Specific Issues

The type of application you are importing partially determines how much effort will be required to get it up and running. A simple C/C++ Mach-O console application, created from the CodeWarrior Mac OS C or C++ Stationery, may require no changes. After importing, it may simply require a rebuild, and then run as expected. A Carbon Mach-O or Cocoa project may require a little more tweaking.

Sometimes the importer may not find or import every file. For example, if your CodeWarrior project included a MainMenu.nib file, but it does not appear in the Xcode project, then you need to manually add it before running (though the project should build without the .nib file). The easiest way to add an existing file to an Xcode project is to use the Finder: drag and drop the file onto one of the file groups on the left-side of the Xcode project window. Once you drop the file on the project, Xcode creates (and manages) a reference to the file, and includes it in the build.

In addition, Xcode stores application properties in the Info.plist file instead of CodeWarrior's .plc file. CodeWarrior includes a project setting to compile an Info.plist from the .plc file (see Figure 7), so your built CodeWarrior application may already include the Info.plist, even though you cannot see it in the project.

Figure 7: The CodeWarrior Setting For Generating an Info.plist File

Finding the file may be a little tricky, since it may be inside the application bundle. In the Finder, you can right-click on the application icon and select Show Package Contents to display the bundle contents, as shown in Figures 8a and 8b. Copy Info.plist to another folder, and then add it to the Xcode project. Typically you will add Info.plist under the Resources group in the Xcode project.

Figure 8a: Selecting Show Package Contents...

Figure 8b: ...Opens the Package Contents in a New Window

You may also need to tweak the path setting for the project Info.plist. This is easy enough using an Xcode Inspector window. Double-click on the desired build target (listed under Targets) in the project window, select the Build tab in the window that, and scroll down to the setting Info.plist File. Click the Edit button, and then specify the path to the file. If it is in the root project folder, you can simply type in Info.plist, click OK, and then rebuild or rerun.

If your CodeWarrior project uses statically-linked C runtime libraries, such as crt1.o (the Metrowerks Standard Library), those libraries may get imported into the Xcode project under the Libraries group. You may need to remove these from the Xcode project to get it to link.

PowerPlant is the CodeWarrior framework and class library that lets you quickly build applications that conform to standard Mac OS appearance and behavior. If your application is a PowerPlant project, you can still import it into Xcode, but you may find that it requires substantially more work than the console, Carbon, and Cocoa applications discussed above. You need to import the PowerPlant libraries into the Xcode project, and include them in the build. More details are available in the document Porting CodeWarrior Projects to Xcode.

Get Ready Now

Xcode is a first-class IDE, and includes many of the same features you're familiar with in CodeWarrior. It's flexible and powerful and in addition, Xcode can build applications that run on both PowerPC and Intel-based Macintosh computers. Apple continually updates Xcode with new features, frameworks, and APIs, enabling you to deliver cutting-edge applications to your customers. If you currently use CodeWarrior, you will find that moving your application to Xcode opens up new opportunities while providing a comfortable development environment that is relatively easy to learn. But don't wait. The first Intel-based Macintosh computers are already shipping to customers, and they will be looking for applications that make the most of the new architecture. Make sure that your application is ready.

For More Information

If you are ready to learn more, visit the Developer Transition Resource Center, where you will find resources that provide everything you need to make sure your applications are ready for both the PowerPC and Intel architectures. The DTRC includes introductory articles, in-depth technical publications, WWDC session videos, and tools for download.

To download the latest version of Xcode, see the Tools topic page.

Posted: 2005-11-28