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wtf is runvt?

mockbatheborg/runvt — explained in plain English

Analysis updated 2026-05-18

2CAudience · developerComplexity · 3/5Setup · moderate

TL;DR

A minimal VT100/ANSI terminal emulator window for running command-line programs, built as a console for a CP/M emulator project.

Mindmap

mindmap
  root((RunVT))
    What it does
      Emulates VT100 ANSI terminal
      Hosts other programs
      Renders in own window
    Tech stack
      C language
      SDL2 graphics
      MinGW cross-compile
    Use cases
      Console for CP/M emulator
      Run shells and editors
      Embed directly in C apps
    Audience
      Retro computing hobbyists
      C developers
      Emulator builders

Code map

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Why would anyone build with this?

REASON 1

Run a CP/M emulator or other command-line program inside a predictable, fixed-size terminal window.

REASON 2

Get accurate VT100/ANSI terminal behavior for retro computing tools without relying on your OS terminal settings.

REASON 3

Embed the terminal emulator directly into another C program instead of spawning it as a separate process.

What's in the stack?

CSDL2MinGW

How it stacks up

mockbatheborg/runvtcode-my-spec/ear_witnessdouglascorrea/syscall-agent
Stars222
LanguageCCC
Setup difficultymoderatehardmoderate
Complexity3/54/54/5
Audiencedeveloperdeveloperdeveloper

Figures from each repo's GitHub metadata at analysis time.

How do you spin it up?

Difficulty · moderate Time to first run · 30min

Requires a C compiler and the SDL2 development library installed before building.

No license information was found in the README.

Wtf does this do

RunVT is a small terminal emulator, meaning a program that displays text and colors the same way old-school computer terminals did, and lets you run other command-line programs inside it. It opens its own window on your screen and understands the VT100 and ANSI standards, which are the classic rules that determine how a terminal shows cursor movement, colors, and text formatting. The author originally built it as a companion for their own separate project, an emulator for old CP/M-based computers, but RunVT itself does not know anything about that specific program. It simply runs whatever command-line program you point it at and displays that program's output the way a terminal would. You could run a shell, a text editor, or the CP/M emulator inside it just the same. What sets RunVT apart from your everyday terminal window is that it is deliberately minimal and predictable. It has a fixed size decided when you launch it, no scrollback history, no tabs, and no settings files to configure. It shows a status bar at the bottom with basic info like the cursor position, and it supports things like colored text, line-drawing characters, an old graphics format called sixel for showing images, clipboard pasting, and typing accented characters correctly. To build it yourself, you need a C compiler and a graphics library called SDL2. Building produces a single program file with no separate installation step. There is also a way to build a Windows version by cross-compiling from Linux, and the README documents in detail a tricky compatibility issue the author ran into with how Windows handles terminal output differently from Linux. This project is aimed at developers and hobbyists working with retro computing emulators or command-line tools who want a simple, dependable terminal window without the complexity of a full-featured terminal application.

Yoink these prompts

Prompt 1
Explain what VT100 and ANSI terminal standards are and why RunVT implements them.
Prompt 2
Walk me through building RunVT from source on Linux with SDL2.
Prompt 3
What is the difference between running RunVT as a standalone program versus embedding it in RunCPM?
Prompt 4
Explain the ConPTY compatibility issue this project ran into on Windows.

Frequently asked questions

wtf is runvt?

A minimal VT100/ANSI terminal emulator window for running command-line programs, built as a console for a CP/M emulator project.

What language is runvt written in?

Mainly C. The stack also includes C, SDL2, MinGW.

What license does runvt use?

No license information was found in the README.

How hard is runvt to set up?

Setup difficulty is rated moderate, with roughly 30min to a first successful run.

Who is runvt for?

Mainly developer.

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