marler8997 / zigx

zigx

An x11 client library for Zig applications.

Currently tested with zig version 0.11.0.

What you should know about X

X is a protocol for transmitting graphics primitives and user inputs.

Components

XClient - a program that connects to an XServer to send graphics primitives and receive user inputs

XServer - a program that accepts XClients to receive graphics primitives and send user inputs

The DISPLAY environment variable

XClient libraries use the DISPLAY environment variable to know how to connect to the XServer. It uses this format:

[PROTOCOL/]HOST:DISPLAYNUM[.SCREEN]

Examples:

# connect to localhost port 6000
:0

# connect to host "foo" port 6003
foo:3

# connect to host "foo" port 6007 screen 5
foo:7.5

Here are some examples of starting XClient programs and settings the DISPLAY environment variable:

# set the XSever
export DISPLAY=:0

# start a couple XClient programs
./my-cool-x-program &
./another-cool-x-program &

# start this program and connect it to the XServer on host "mymachine" running on port 6010 screen 1
DISPLAY=mymachine:10.1 ./yet-another-x-program

How to debug an X connection

# -n means do not copy credentials
xtrace -n -- command

# i.e.
xtrace -n -- zig run example.zig

Authentication

https://en.wikipedia.org/wiki/X_Window_authorization

• MIT-MAGIC-COOKIE: implemented for local connections
• XDM-AUTHORIZATION-1: not implemented

For XDM-AUTHORIZATION-1, a secret key is stored in the $HOME/.Xauthority file, the client creates a string by concatenating the current time, a transport identifier and the key, then encrypts the resulting string and sends it to the server.