Any programmer accustomed to writing programs on Linux or System V-type Unixes will have encountered the program variously known as strace or truss, which monitors another program and produces a detailed log of every system call the program makes - in other words, all the program's interactions with the OS kernel. This is often an invaluable debugging tool, and almost as good an educational one. When it's a GUI program (or rather, the GUI-related behaviour of a program) that you want to understand or debug, though, the level of interaction with the OS kernel is rarely the most useful one. More helpfully, one would like to log all the program's interactions with the X server in the same way. This package provides xtruss, an X protocol loggers. It has a command-line syntax similar to strace in its default mode, you just prefix "xtruss" to the same command line you would have run anyway and its output format is also more like strace, putting requests and responses on the same line of output where reasonably possible.