pappl-sys 0.1.0

# pappl-sys

Raw bindgen FFI bindings for [PAPPL](https://www.msweet.org/pappl/), Michael
Sweet's Printer Application Programming Library.

This crate is the unsafe layer. For typed handles, builders, and a `DeviceScheme`
trait that hides the `unsafe extern "C" fn` callback boilerplate, use
[`pappl-rs`](https://crates.io/crates/pappl-rs).

## Status

Released as-is. The original authors no longer use PAPPL in their own
projects; we publish this in case it's useful to others. PRs welcome, but
active maintenance is best-effort.

## Build requirements

| Package | Why |
|---|---|
| `libpappl-dev` ≥ 1.0 | the C library and headers (probed via `pkg-config`) |
| `libcups2-dev` | PAPPL pulls CUPS types into its public headers |
| `libclang-dev` | bindgen runs clang to parse the headers |
| `pkg-config` | locates the above |

On Debian/Ubuntu:

```sh
sudo apt install libpappl-dev libcups2-dev libclang-dev pkg-config
```

## PAPPL version matrix

| PAPPL | Builds? | Notes |
|---|---|---|
| ≥ 1.4 | ✓ | Full API including `papplSystemCreatePrinters` (gated by `cfg(pappl_1_4)`, exposed via the `try_system_create_printers` wrapper in `lib.rs`). |
| 1.0 – 1.3.x | ✓ | Older symbol set; the 1.4-only wrapper degrades to a no-op returning `false`. |
| < 1.0 | ✗ | `pkg-config` fails the build with a clear version error. |

This crate does NOT track the PAPPL ABI across versions automatically.
If the C library changes a public-struct layout you'll need to rebuild
against the new headers.

## Why `links = "pappl"`?

Cargo enforces a single instance per process; if two crates in a build
both pulled in `pappl-sys` with conflicting versions you'd get a duplicate-
symbol mess at link time. The `links` key makes Cargo refuse that earlier
and louder.

## Re-generating bindings

Bindings are regenerated from `wrapper.h` on every build. `wrapper.h`
includes only `<pappl/pappl.h>`; if you need extra PAPPL headers (e.g.
internals not in the public umbrella header), edit `wrapper.h` and the
`allowlist_*` calls in `build.rs`.

## License

MIT — see [`LICENSE-MIT`](../../LICENSE-MIT) at the repo root.