• Minimal Clap Host
• Notes on static build vs dynamic build
• Building on macOS
  • dynamic build using brew (recommended)
  • static build using vcpkg
• Building on Windows
  • Enable long path support
  • static build
• Building on Linux
  • dynamic build using system libraries
  • static build using vcpkg
• Running on macOS
  • Keyboard inputs

Minimal Clap Host

This repo serves as an example to demonstrate how to create a CLAP host.

Notes on static build vs dynamic build

The host uses Qt for its GUI. It is fine to dynamically link to Qt, but it is not for a plugin. We offer two options:

• static build, cmake preset: ninja-vcpkg or vs-vcpkg on Windows.
• dynamic builg, cmake preset: ninja-system

Static builds are convenient for deployment as they are self containded.

Dynamic builds will get your started quickly if your system provides Qt6. Static builds will require more time and space.

Building on macOS

dynamic build using brew (recommended)

# Install dependencies
brew install qt6 pkgconfig rtaudio rtmidi ninja cmake

# Checkout the code
git clone --recurse-submodules https://github.com/free-audio/clap-host
cd clap-host

# Build
cmake --preset ninja-system
cmake --build --preset ninja-system

static build using vcpkg

# Install build tools
brew install cmake ninja autoconf automake pkg-config libtool

# Checkout the code
git clone --recurse-submodules https://github.com/free-audio/clap-host
cd clap-host
scripts/build.sh

Building on Windows

Enable long path support

Make sure your system supports long paths. Run this in an administrator PowerShell:

New-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Control\FileSystem" -Name "LongPathsEnabled" -Value 1 -PropertyType DWORD -Force

Reference: https://docs.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation?tabs=powershell

static build

Install Visual Studio 2022; you can install it from the Microsoft Store. It can also install git and CMake for you.

Use the following command inside git-bash:

# Checkout the code very close to the root to avoid windows long path issues...
cd c:\
git clone --recurse-submodules https://github.com/free-audio/clap-host c-h
cd c-h

scripts/build.sh

Building on Linux

dynamic build using system libraries

# on archlinux, adapt to your distribution and package manager
sudo pacman -S qt git ninja cmake rtaudio rtmidi

git clone --recurse-submodules https://github.com/free-audio/clap-host
cd clap-host
cmake --preset ninja-system
cmake --build --preset ninja-system

static build using vcpkg

git clone --recurse-submodules https://github.com/free-audio/clap-host
cd clap-host
scripts/build.sh

Running on macOS

Once you have built clap-host, you can access the Debug binary from the repo root at:

> cd ./builds/ninja-system/host/Debug
> ./clap-host --help
Usage: ./clap-host [options]
clap standalone host

Options:
  -h, --help                         Displays help on commandline options.
  --help-all                         Displays help, including generic Qt
                                     options.
  -v, --version                      Displays version information.
  -p, --plugin <path>                path to the plugin
  -i, --plugin-index <plugin-index>  index of the plugin to create

Then load your plugin via:

> ./clap -p /Library/Audio/Plug-Ins/CLAP/<your-plugin>.clap

Note: the --plugin flag currently does not work, so use -p. Also, paths with ~ don't resolve (but paths with .. do).

Keyboard inputs

If your plugin is a synthesizer, you can send NoteOn events via your computer keyboard to test things out:

• Keys Z - M: C2 - B2 (S - J cover sharps / flats)
• Keys Q - I: C3 - B3 (2 - 9 cover sharps / flats)

(This may only work for your CLAP plugin's default preset).