Guides

CircleMUD with open-source tools

This guide details the process of compiling and initializing CircleMUD 3.1 on modern Linux distributions. It addresses specific legacy C compilation hurdles, configuration of the internal directory structure, and the initial server boot sequence required to establish a stable development environment.

45 minutes6 steps
CircleMUD with open-source tools hero illustration
1

Install System Dependencies

Modern Linux distributions often decouple the crypt library from the standard C library. You must install the development headers to ensure the CircleMUD password hashing functions link correctly during compilation.

sudo apt-get update && sudo apt-get install build-essential libcrypt-dev

⚠ Common Pitfalls

  • •Failure to install libcrypt-dev will result in 'crypt' undefined reference errors during the linking stage.
2

Configure the Build Environment

Run the included configure script to generate the appropriate Makefile for your architecture. Because CircleMUD uses an older version of Autoconf, you may need to force certain environment variables if your system uses non-standard library paths.

cd src && ./configure

⚠ Common Pitfalls

  • •If the configure script fails to detect your compiler, ensure 'gcc' is in your PATH.
  • •On some 64-bit systems, you may need to add CFLAGS='-m64' if you are targeting a specific architecture.
3

Patch Makefile for Modern GCC

GCC 10 and later changed the default behavior for global variables (fno-common). CircleMUD relies on legacy 'common' behavior where multiple definitions of the same global variable in different source files are merged. You must append -fcommon to the CFLAGS.

src/Makefile
sed -i 's/CFLAGS = -g -O2/CFLAGS = -g -O2 -fcommon/g' Makefile
4

Compile the Binary

Execute the make command within the src directory. This will produce the 'circle' executable. It is recommended to use the '-j' flag to speed up compilation if you have multiple CPU cores.

make -j$(nproc)

⚠ Common Pitfalls

  • •Warnings about 'deprecated conversion from string constant' are common in CircleMUD and can generally be ignored for the initial build.
  • •If compilation fails at 'act.wizard.c', check for missing headers related to system limits.
5

Configure Port and Directory Settings

CircleMUD reads its operational parameters from the lib/etc/config file. You must ensure the port is set to an open value (usually 4000) and that the directory paths match your local installation.

lib/etc/config
PORT=4000
IP_ADDRESS=
LOG_LEVEL=2
6

Initialize the World and Boot

Move the compiled binary to the bin directory and use the autorun script. The autorun script is vital because it handles automatic reboots if the MUD crashes and manages log rotation in the 'log' directory.

cd .. && ./bin/circle -p 4000

⚠ Common Pitfalls

  • •If the MUD fails to boot, check 'log/syslog' immediately. The most common cause is missing zone or world files in the lib/world/ directory.
  • •Ensure the 'lib' directory has write permissions for the user running the process, or player files cannot be saved.

What you built

With the binary compiled and the server running, you can connect via any Telnet client to localhost:4000. The first character created will automatically be granted Implementor (Level 34) status if it is the first account in the system, allowing you to begin using On-Line Creation (OLC) tools to build your world.