# Building (radare2 integration notes)

The canonical build instructions — dependencies, per-platform install
commands, environment overrides — live in **[../BUILD.md](../BUILD.md)**.

This file keeps the radare2 vendoring and binary-backend integration
notes that don't belong in the top-level quick-start.

## radare2 binary backend

The binary backend links against radare2's `libr_core` when
`pkg-config` can find `r_core.pc` (for example under
`/usr/local/lib/pkgconfig` or Homebrew's prefix). If the development
package is not present, fold still builds and uses the `r2`
command-line fallback at runtime.

```sh
# Require linked radare2 support at configure time
meson setup build/release --reconfigure -Dradare2=enabled

# Disable linked radare2 support and rely on the CLI fallback
meson setup build/release --reconfigure -Dradare2=disabled
```

Vendoring radare2 should be done through a build-system dependency
path (Meson subproject/wrap or pinned external source in CI), not by
committing the full upstream tree into `src/`. fold is GPL-3.0-only,
so radare2's GPL-compatible builds are license-compatible, but the
upstream project is large and has plugin ABI concerns. The preferred
clean integration is:

1. Build/pin radare2 in CI or a Meson subproject.
2. Expose `r_core.pc` to fold's Meson configure step.
3. Compile fold with `-Dradare2=enabled`.

This keeps the binary backend using stable `libr_core` APIs while
avoiding a large vendored source tree in normal checkouts.

## Binary backend integration test

The optional `binary_backend` integration test uses radare2 and a
real binary. Defaults to `/usr/bin/curl` when available, can be
redirected via:

```sh
FOLD_TEST_BINARY=/path/to/binary meson test -C build/release binary_backend
```

The test skips itself when no suitable binary or `r2` command is
present.