XCode tech notes

 

return to topCheat sheet for <ctime> and <time.h>

When coding with <ctime>, I can never keep all the functions and their arguments straight. So I made this handy cheat sheet. Click the image to see the PDF version.

ctime-cheat-sheet

Click image to enlarge

Keywords for indexing: time_t strptime strftime mktime timegm timelocal gmtime localtime asctime.

return to topDylibs: "no suitable image found"

[OS 10.10.5 Yosemite XCode 7.2.1]

Problem: After successfully building and deploying a dynamic library, you might get an error like this when running a program that links against it:

dyld: Library not loaded: /./librt130.dylib Referenced from: /Users/jtb/Library/Developer/Xcode/DerivedData/...... Reason: no suitable image found.

I know the library was installed in /opt/earthsound/lib/, so there's something definitely fishy about that path (/./librt130.dylib). Let's see what otool has to say about this dylib's install name:

% otool -D /opt/earthsound/lib/librt130.dylib /opt/earthsound/lib/librt130.dylib: /./librt130.dylib %

The "install name" of the dylib is definitely wrong.

Fix: In XCode, go to the Build Settings for this target, and look for "Dynamic Library Install Name" under the "Linking" section:

Delete the offending entry (/./librt130.dylib) and rebuild the library. The library should now have the correct "install name":

% otool -D /opt/earthsound/lib/librt130.dylib /opt/earthsound/lib/librt130.dylib: /opt/earthsound/lib/librt130.dylib %

Programs will now be able to use the dylib as expected.

return to topSome handy command-line diagnostic tools

[OS 10.10.5 Yosemite XCode 7.2.1]

% file someFile Reports the type and architecture of someFile.
% otool Gives useful info about a dynamic or static library.
Example: otool -L fooLib lists the other shared libraries used in library fooLib

return to topdyld: lazy symbol binding failed

[OS 10.10.5 Yosemite XCode 7.2.1]

Problem: An executable that runs just fine on the development machine generates a "lazy symbol binding" error when it's run on the (supposedly "identical") deployment machine. In this example, the executable usgsEvents runs fine on the dev machine ("paris.local"):

paris.local% usgsEvents Found 12 events: Thu May 5 13:49:30 2016 3.8 -113.99 36.48 0 Nevada (35km SSE of Bunkerville, Nevada) Thu May 5 22:27:06 2016 5.5 -107.12 18.67 0 Mexico (241km SW of Tomatlan, Mexico) ...(etc.)... paris.local%

When run on the deployment machine ("broadcaster.local") it throws this error:

broadcaster.local% usgsEvents dyld: lazy symbol binding failed: Symbol not found: __ZN8jtbUtils14LocalTimeToUTCEPl Referenced from: /opt/earthsound/bin/usgsEvents Expected in: /opt/earthsound/lib/libjtb_utils.dylib dyld: Symbol not found: __ZN8jtbUtils14LocalTimeToUTCEPl Referenced from: /opt/earthsound/bin/usgsEvents Expected in: /opt/earthsound/lib/libjtb_utils.dylib Trace/BPT trap broadcaster.local%

In other words, the executable's symbol jtbUtils::LocalTimeToUTC is missing from the dylib on the deployment machine.

Fix: Double-check that the dylib on the deployment machine is up-to-date with the one on the dev machine.

It's in the category of "duh", but I need the reminder.

return to topWhen Macports 'selfupdate' fails

[OS 10.10.5 Yosemite XCode 7.1]

Problem: After upgrading to XCode 7.1, an attempt to update Macports fails:

% sudo port -v selfupdate ---> Updating MacPorts base sources using rsync receiving file list ... done base.tar sent 31276 bytes received 230167 bytes 27520.32 bytes/sec ...... SNIP (skipping lots of lines) ...... checking Xcode location... /Applications/Xcode.app/Contents/Developer checking Xcode version... 7.1 checking whether the C compiler works... no configure: error: in `/opt/local/var/macports/sources/rsync.macports.org/release/tarballs/base': configure: error: C compiler cannot create executables See `config.log' for more details Command failed: cd /opt/local/var/macports/sources/rsync.macports.org/release/tarballs/base && CC=/usr/bin/cc OBJC=/usr/bin/cc ./configure --prefix=/opt/local --with-install-user=root --with-install-group=admin --with-directory-mode=0755 --enable-readline && make SELFUPDATING=1 && make install SELFUPDATING=1 Exit code: 77 Error: Error installing new MacPorts base: command execution failed To report a bug, follow the instructions in the guide: http://guide.macports.org/#project.tickets Error: /opt/local/bin/port: port selfupdate failed: Error installing new MacPorts base: command execution failed %

Fix: Accept the new XCode license:

% sudo xcodebuild -license

Follow the instructions to accept the new license. sudo port selfupdate should now work properly.

If you still have problems, double-check that you have the XCode command-line tools installed:

% sudo xcode-select --install

return to topWorking with XCode and git

[OS 10.10.3 Yosemite XCode 6.3.1]

Migrating an existing XCode project to git
  1. Create a remote repo on github, Bitbucket, etc. Be sure to create a .gitignore for C++ and a README.md.
  2. To the .gitignore file append this line at the end:

    # Macintosh cruft .DS_Store

  3. Make a note of the URL to the remote repo (we'll call it "URL_TO_REMOTE_REPO")
  4. On your local computer:

    % cd path/to/my/project % git init % git add . % git remote add origin URL_TO_REMOTE_REPO % git pull origin master

  5. Open your project in XCode. (If XCode was already open when you did the previous step, you may need to re-launch it.)
  6. Open XCode's project navigator. Notice that each of the source code files is listed with an accompanying "?", to indicate that it has not yet been committed to the local repo.
  7. In XCode's project navigator, select all the files flagged with "?", then pull down Source Control > Add Selected Files (or right-click and select Source Control > Add Selected Files).
  8. Pull down Source Control > Commit..., enter a commit message, and check the Push to remote checkbox.
  9. Visit your remote repo on github or Bitbucket to confirm that all the files are there.

Your project is now successfully sync'ed with the remote repo. From here on, you can push your code changes to the remote repo using XCode's Source Control > ... menu.

To confirm that everything's working, check out the repo to a second Mac, and build the project. If the build fails because of missing #include files or libraries, make sure that those files on Mac #2 have the same paths, relative to the project, that they had on Mac #1. It's a good idea to use the same file hierarchy structure on all the Macs you'll be building on.

Tagging

Because XCode 6 does not support git tagging, tags have to be handled manually, via the command line.

  1. Launch a terminal window and go into your local project folder:

    % cd path/to/my/project

  2. List the tags that git already knows about:

    % git tag %

  3. Tag the current version and provide a useful commit message:

    % git tag -a v0.01 -m "Tagging version 0.01" %

  4. List the tags that git knows about:

    % git tag v0.01 %

  5. Push the tag to the remote repo:

    % git push --tags Counting objects: 1, done. Writing objects: 100% (1/1), 155 bytes | 0 bytes/s, done. Total 1 (delta 0), reused 0 (delta 0) To git@bitbucket.org:[USERNAME/PROJECT].git * [new tag] v0.01 -> v0.01 %

Other git one-liners:

Checkout a particular tag % git checkout tags/v0.003
rename a file % git mv oldFileName newFileName
add and commit a file to the remote

% git add SOME_NEW_FILE % git commit -m "Adding an awesome new feature!" % git push origin master

list branches % git branch
delete local branch % git branch -D branchName
set aside local changes % git stash
throw out the stash % git stash drop
apply the stash to the local % git stash apply

return to top Be conservative with header search path settings

[XCode 6.2 / OS 10.10.2 Yosemite]

Problem: After months of trouble-free use, XCode builds suddenly started throwing tons of errors like this:

"Unknown type name 'uint_8'" In file included from /opt/earthsound/src/lookback/lookback/RTFilename.cpp:1: /opt/earthsound/src/lookback/lookback/RTFilename.h:8:10: In file included from lookback/RTFilename.h:8: /opt/local/include/boost/tr1/tr1/iostream:16:12: In file included from /opt/local/include/boost/tr1/tr1/iostream:16: /opt/local/include/boost/tr1/detail/config_all.hpp:48:10: In file included from /opt/local/include/boost/tr1/detail/config_all.hpp:48: /opt/local/include/boost/compatibility/cpp_c_headers/cstdlib:8:10: In file included from /opt/local/include/boost/compatibility/cpp_c_headers/cstdlib:8: /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/ SDKs/MacOSX10.10.sdk/usr/include/stdlib.h:65:10: In file included from /Applications/Xcode.app/Contents/Developer/Platforms/ MacOSX.platform/Developer/ SDKs/MacOSX10.10.sdk/usr/include/stdlib.h:65: /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/ SDKs/MacOSX10.10.sdk/usr/include/sys/wait.h:110:10: In file included from /Applications/Xcode.app/Contents/Developer/Platforms/ MacOSX.platform/Developer/ SDKs/MacOSX10.10.sdk/usr/include/sys/wait.h:110:

Similarly, these:

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/ SDKs/MacOSX10.10.sdk/usr/include/inttypes.h:235:8: Unknown type name 'intmax_t' /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/ SDKs/MacOSX10.10.sdk/usr/include/sys/resource.h:195:2: Unknown type name 'uint8_t' /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/ SDKs/MacOSX10.10.sdk/usr/include/sys/resource.h:196:2: Unknown type name 'uint64_t' ...

Long story short: XCode was loading the wrong headers. My target's "Header Search Paths" build settings contained /opt/local/include/** and /opt/local/lib/**, which is way too generous! This caused countless non-standard header files from my (recently updated) MacPorts ports tree to be loaded into the precompiler.

Fix: Remove /opt/local/include/** and /opt/local/lib/** from the "Header Search Paths" build settings. Replace them with much more specific paths to the desired include directories. In my particular case, this meant replacing them with /opt/local/include/glib-2.0 /opt/local/lib/glib-2.0/include /opt/local/include/. It's up and running again!

return to top MacPorts cheat-sheet

[XCode 6.1.1 / OS 10.10.1 Yosemite]

Where to find the docs MacPorts Guide
customize MacPorts % vi /opt/local/etc/macports/macports.conf
update the ports tree % sudo port -v selfupdate
show what's installed % port installed
search for available ports % port search zzzzzzz
show which ports are outdated % port outdated
remove all previously installed ports % sudo port -f uninstall installed
upgrade outdated ports % sudo port upgrade outdated
install a port % sudo port install zzzzzzz
Managing multiple port versions
By default, /opt/local is reserved for MacPorts. Don't put anything else in there! You can, however, keep multiple MacPorts instances on your computer — just install them somewhere else. I keep my primary ports in /opt/local (the default), but keep builds for 32-bit architectures in /opt/loc32. The MacPorts config file for the 32-bit ports lives in /opt/loc32/etc/macports/macports.conf. Make sure you know which instance of port is in your PATH environment, or you'll drive yourself crazy building the wrong ports!

return to top Where do the debug builds reside?

[XCode 4.5.2 / OS 10.7.5]

Q: When running a debugging scheme for a command-line program, where does the build actually reside?

A: It lives in the build target directory. But during a debugging session, XCode uses a symbolic link to that file. To find that symlink, start by looking in ~Library/Developer/Xcode/DerivedData. Then cd into the subdir whose name starts with that of your project, followed by an absurdly long string of gibberish characters. From there, look in the subdir Build/Products/Debug.

For example: ~/Library/Developer/Xcode/DerivedData/myproject-bayrxljwsuqsqtwekudskvvscruc/Build/Products/Debug.

Why should you care? Because if your CLP takes a file path as an argument (that you've specified in the XCode scheme settings), the XCode debugger will look for that path relative to the above DerivedData directory (instead of relative to the target build directory), and your CLP will probably not work as you intended. Phfft.

return to top Building against GLib

(XCode 4.5.2)

Problem: When building a project that uses glib, the compiler may throw this error:

'glibconfig.h' file not found.

Fix: In my case, where I've installed GLib to /opt/local/, most of GLib's header files are in /opt/local/include/glib-2.0/. But the GLib installation also puts glibconfig.h at /opt/local/lib/glib-2.0/include/glibconfig.h. XCode's target build settings must therefore include both directories in its Header Search Paths. In my case, the error goes away when I change Header Search Paths to include both /opt/local/include/** and /opt/local/lib/**.

return to top Stack corruption

[XCode 4.5.2]

Problem: Very flaky runtime segmentation fault. Xcode debugger stack trace revealed that when a vector container was instantiated in a class residing in a dylib, main() would disappear from the stack. Upon completion of the instantiation, execution would (understandably) halt, spewing this error:

Address doesn't contain a section that points to a section in a object file.

Fix: In the XCode project settings, select the active target, and look for the preprocessor macro settings. Delete _GLIBCXX_DEBUG=1 _GLIBCXX_DEBUG_PEDANTIC=1 . See also "Stringstream doesn't convert integers to strings", below.

return to top stringstream doesn't convert integers to strings

[XCode 4.2.1]

Problem: This code

stringstream ss; ss << "This is the answer: " << 42 << ". OK?" << endl; cout << ss;

should generate output like this:

This is the answer: 42. OK?

Instead, it looks like this:

This is the answer:

due to a bug in the GCC compiler in XCode debug mode. Note that everything from the first integer onwards is dropped.

Fix: In the XCode project settings, select the active target, and look for the preprocessor settings. Delete _GLIBCXX_DEBUG=1 _GLIBCXX_DEBUG_PEDANTIC=1 . See stackoverflow.com.

return to top CpResource error: "...is longer than MAXPATHLEN (1024)"

Problem: During the build Xcode [4.2.1] throws a "... is longer than MAXPATHLEN" error.

CpResource /Users/jtb/Library/Developer/Xcode/DerivedData/maxcpp2-ambxcvcbiofkwfambuwyfqekivbj/ Build/Products/Debug/example2.mxo /Users/jtb/lib/MaxExterns/example2.mxo/Contents/Resources/example2.mxo cd /Users/jtb/src/maxcpp2 builtin-copy -exclude .DS_Store -exclude CVS -exclude .svn -exclude .git -exclude .hg -resolve-src-symlinks /Users/jtb/Library/Developer/Xcode/DerivedData/maxcpp2-ambxcvcbiofkwfambuwyfqekivbj/ Build/Products/Debug/example2.mxo /Users/jtb/lib/MaxExterns/example2.mxo/Contents/Resources error: '/Users/jtb/lib/MaxExterns/example2.mxo/Contents/Resources/example2.mxo/ Contents/Resources/example2.mxo/Contents/Resources/example2.mxo/Contents/Resources/ example2.mxo/Contents/Resources/example2.mxo/Contents/Resources/example2.mxo/Contents/ Resources/example2.mxo/Contents/Resources/example2.mxo/Contents/Resources/example2.mxo/ Contents/Resources/example2.mxo/Contents/Resources/example2.mxo/Contents/Resources/ example2.mxo/Contents/Resources/example2.mxo/Contents/Resources/example2.mxo/Contents/ Resources/example2.mxo/Contents/Resources/example2.mxo/Contents/Resources/example2.mxo/ Contents/Resources/example2.mxo/Contents/Resources/example2.mxo/Contents/Resources/ example2.mxo/Contents/Resources/example2.mxo/Contents/Resources/example2.mxo/Contents/ Resources/example2.mxo/Contents/Resources/example2.mxo/Contents/Resources/example2.mxo/ Contents/Resources/example2.mxo/Contents/Resources/example2.mxo/Contents/Resources/ example2.mxo/Contents/Resources/example2.mxo/Contents/Resources/example2.mxo/Contents/ Resources/example2.mxo' is longer than MAXPATHLEN (1024).

Fix: In the project navigator, select the product that you're trying to build. In the Utility area, click on the file inspector icon. Look for the "Target membership" tab. Make sure that the targets are unchecked. This avoids that recursive file path loop during the build.

return to top Loader warning: visibility settings

[XCode 4.2.1]

Problem: XCode 4.2.1 loader issues this warning:

ld: warning: direct access in __ZN9__gnu_cxx26__concurrence_unlock_errorC2Ev to global weak symbol __ZTVN9__gnu_cxx26__concurrence_unlock_errorE means the weak symbol cannot be overridden at runtime. This was likely caused by different translation units being compiled with different visibility settings.

Fix: In project (or product) settings, look for "Code Generation" > "Hidden Local Variables". Set this to "No" and build the project again. Works for me.

return to top Navigating the search path jungle

Problem: The relationships between the various search path settings baffle me. There are Preference panels for both the Target and the Project (can’t figure out which has priority over the other); within those there are settings for the SDK Path and Library Search Paths. When I try to link to a library (say, xyz.dylib) in /usr/local/lib, it appears that it is not sufficient to simply add this path to the Library Search Paths: the link editor complains that it can’t find /Developer/SDKs/MacOSX10.4u.sdk/usr/local/lib/xyz.dylib . No surprise there, because the SDK Path setting says that the SDK path is prepended before all library paths. But when I put "../../../usr/local/lib" in Library Search Paths, the linker complains that it can’t find "../../../usr/local/xyz.dylib." Huh? Where’s the prepend? Harrumph.

Kludge: Put "/usr/local/lib" in Library Search Paths and create a symbolic link to that directory:

% cd /Developer/SDKs/MacOSX10.4u.sdk/usr % ln -s /usr/local ./local

XCode’s linker now finds the library OK.

return to top Compiler: type ‘std::deque....’ is not derived from ‘...’

Compiler error:

error: type ‘std::deque<T_Shell<T>::builtin, std::allocator<T_Shell<T>::builtin> >’ is not derived from type ‘T_Shell<T>’

Fix: Change

typedef deque<builtin>::const_iterator cBuiltinIterator;

To:

typedef typename deque<builtin>::const_iterator cBuiltinIterator;

return to top Compiler error: template with C linkage

Compiler error:

error: template with C linkage

Fix: move /usr/include to somewhere else (e.g., ~/src/usr_include) and edit XCode’s header search path accordingly (Project > Edit project setttings > Build > Collection: Search paths > Header search paths).

return to top Loader: cputype mismatch?

Problem: Loader complains about an architecture mismatch between the project and a dynamic library:

/usr/bin/ld: warning /Developer/SDKs/MacOSX10.4u.sdk/usr/local/lib/libsndfile.1.0.17.dylib cputype (18, architecture ppc) does not match cputype (7) for specified -arch flag: i386 (file not loaded)

This error does not appear with the Debug build; only with the Release build. And I swear I never did an i386 build (why would I want to??).

Fix: Clean the project (both the Debug and Release). In the Project Settings, choose the Architectures setting and set it to "ppc i386". Rebuild. Clean again. Now change the setting back to "ppc". Rebuild. Success! — just don’t ask me why.

Follow-up [071110]: Mike V sent in the following info:

I had the same problem when linking "-arch i386" while trying to link with ppc only dynamic library; I tried your sulution but still was getting i386 as a separate build.

I tried changing Project Settings -> Cross-Develop Using Target: from 10.4 (Universal) to Current Mac,it still gave me a list of undefined symbols i was able to pass a number of files that has been compiled.

What fixed the problem when i did

grep -R ’i386’ my_pro..xcodeproj

and found the line with ARCH, which is also mentioned in here.

here is the line(s):

... /* Release */ = { isa = XCBuildConfiguration; buildSettings = { ARCHS = ( ppc, i386, );

Removing/uncommenting i386 solves the problem!!! also if i comment it out xcode will remove the line afterwards by itself.

Apparently when i first open build options you have

Architectures set to "$(NATIVE_ARCH)"

Maybe what you can emphasize in your notes is that you need to double click these values NOT to enter them manually. e.g "ppc i386" instead of "$(NATIVE_ARCH) i386" which i have done, because it still displayed "ppc i386" after i clicked <enter> to end editing the Architectures field.

I would highly recommend updatin this information for your tutorial (not that i’ve discovered it, just that i was quite frustraded and dont want this for other people) 8D

Thanks, Mike!

return to top Compiler: class ‘...’ has no field named ‘...’

Compiler error:

error: class ’Gram’ does not have any field named ’T_Packet’

Change:

Gram :: Gram(string aName,int ns) : T_Packet(aName, Gram_PACKET_TYPE, Gram_WORDTYPENAME, Gram_PACKET_DESC, Gram_PACKET_EXT) { ... }

To:

Gram :: Gram(string aName,int ns) : T_Packet<Gram_DATATYPE>(aName, Gram_PACKET_TYPE, Gram_WORDTYPENAME, Gram_PACKET_DESC, Gram_PACKET_EXT) { ... }

return to top Compiler: conflicting types for built-in function ‘scalb’

Compiler error: conflicting types for built-in function ’scalb’

Fix: Ignore it. This appears to be a known issue with the Apple SDK.

return to top When the debugger or compiler start acting flaky

Now and then the debugger starts acting flaky, losing track of breakpoints and wandering all over the place, no matter how you step into, over, or out the code. At other times, the compiler starts going wild.

Fix: Try one or more of these:
  1. Quit XCode, relaunch, and try again.
  2. Clean, rebuild, and try again.
  3. Create a new project from scratch, copy all the source files into the new project, and try again.

FWIW, #3 is the only one that works reliably for me.

return to top No stdin when debugging a C++ command line utility?

Problem: Can’t enter keyboard input when debugging a C++ command line utility.

Fix: Select Debug->Standard I/O Log. Output will appear in the "Standard I/O" window. You can type tty input there.

return to top How to import libsndfile into a project

libsndfile is an open-source C library to allow programmers to read and write sound files via a simple, standard interface. It handles many formats: WAV, AIFF, Octave, PAF, etc. You, the programmer, don’t have to worry about the dirty business of headers, endian-ness, etc. — libsndfile takes care of all that invisibly. Getting libsndfile to work with XCode projects is fairly straightforward, but in case you (like me) are never quite sure what you’re doing, the following overview may be helpful. Note: By default, the Finder hides root-level directories (/usr, /lib, /etc, etc.,) from dialog boxes. To work with libraries like libsndfile, you have to make them visible.
  1. Compile libsndfile according to the instructions in the README and INSTALL files. Note that the default installation puts sndfile.h in /usr/local/include, and the library itself in /usr/local/lib.
  2. Create a new XCode project
  3. Copy make_sin.c from the libsndfile "examples" directory into your project.
  4. Tell XCode where to find the include file:
    • Project → Edit Project Settings
    • Click "Build"
    • In "Collection" popup, select "Search Paths"
    • Double-click "Header Search Paths" and add the path /usr/local/include if it’s not already listed there. Leave the "Recursive" checkbox unchecked.
    • Click "OK".
    • Double-click "Library Search Paths" and add the path /usr/local/lib if it’s not already listed there. Leave the "Recursive" checkbox unchecked.
    • Click "OK"
    • Close the Project Info window.
  5. Add the library to your project:
    • In the project window, select the project icon in the "Groups and Files" pane.
    • Project → Add to Project... (or control-click the project icon).
    • Navigate to the library you wish to include (probably libsndfile.a. If you want to copy the library to your project (why would you??), click the checkbox. Click "Add."
  6. Compile your project. You may have to do some minor tweaking to make_sin.c to get it to compile. For example, I had to change this: int main (void) to this: int main (int argc, char * const argv[])

That’s all there is to it.

Addendum 070201: After I upgraded to XCode 2.3, the link editor had some problems linking to this library. See Loader issues, above.

return to top XCode keyboard shortcuts

to do this......type this
toggle between source code and include files Cmd-Opt-UpArrow

return to top Don’t use ZeroLink!

With ZeroLink turned on, the program executes, then aborts:

ZeroLink: unknown symbol ’__ZN7T_ShellI9WorkspaceEC1Ev’

With ZeroLink turned off, the build fails, but now the messages are a little more useful:

/usr/bin/ld: Undefined symbols: _AIFF_verbose T_Shell<Workspace>::Init() T_Shell<Workspace>::T_Shell() T_Shell<Workspace>::~T_Shell() SAC::SAC() SAC::~SAC() AIFF::AIFF() AIFF::~AIFF() ... ...{plus lots more}... ... collect2: ld returned 1 exit status

Moral: ZeroLink makes it hard to see what’s going on. Keep ZeroLink turned off so you can debug those loader errors.

return to top How to include non- .h files

Use care when include’ing non .h files in your source code. For example:

  • #include "foo.h" resolves to foo.h, wherever it lives in your nested hierarchy of project dirs.
  • #include "bar.cpp" resolves to ./bar.cpp. If it lives outside this directory, then give it a relative pathname: #include "../foo/bar.cpp"

return to top How to move source files into a new project

After creating a new project, open the project window. Right-click on the "Source" folder in the "Groups & Files" pane. Select Add → Existing Files... and navigate to the files you want to include.

When the popup window appears, check the Copy items into destination group’s folder box. Check the Recursively create groups... radio button. Click Add. Copies of the selected files will be placed in the project source directory.