Swift X11 in Xcode

An example Xcode project showing how to write an X11 app on OS X

Prerequisites

Install Quartz using Homebrew Cask or directly from Sourceforge

$ brew cask install xquartz

After installing XQuartz, you will need to logout. Log back in and ensure the DISPLAY environment variable is set up:

$ echo $DISPLAY
/private/tmp/com.apple.launchd.uk0lyyi1Ny/org.macosforge.xquartz:0

If this is empty, your XQuartz installation may have failed.

Getting Started

Link the header files into /usr/local/include/X11 and libraries into /usr/local/lib/X11:

$ ln -s /usr/X11/include/X11 /usr/local/include
$ ln -s /usr/X11/lib /usr/local/lib/X11

Building using Xcode

In the Xcode project, under build settings, import the following paths to the search path:

1. $(SRCROOT)/CX11 for the CX11 module
2. /usr/local/include/X11 for the X11 headers

Also under build settings, import the following library search path /usr/local/lib/X11:

Under build phases, link the binary with libX11.6.dylib. Under the "Choose frameworks and libraries to add" drop sheet, select "Add Other" and locate /usr/local/lib/X11/libX11.6.dylib.

Building using xcrun and swiftc

Navigate to main.swift

Run:

$ cd /path/to/main.swift
$ xcrun \
    -sdk macosx \                # Include OS X SDK    
    swiftc main.swift \          # Compile main.swift
    -lX11 -L/usr/local/lib/X11 \ # Include X11 dylib
    -I/usr/local/include/X11 \   # Include X11 headers
    -I$(pwd)/../CX11             # Include CX11 module

Screenshot

Attribution

Thanks to @terhechte for his Linux example and CX11 package (slightly modified to support El Capitan's rootless system)