Crate libnotcurses_sys

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Expand description

libnotcurses-sys is a low-level Rust wrapper for the notcurses C library

It is built with several layers of zero-overhead abstractions over the C functions and pointers accessed through FFI.

It adds greater safety and type correctness over the underlying C library API, while trying to remain very close to it.

It offers the choice of using it more like Rust and/or more like C.

Like Rust

Where you use the more safely wrapped types, with its methods and constructors, and error handling with the NcResult enum:

Example

use libnotcurses_sys::*;

fn main() -> NcResult<()> {
    let nc = unsafe { Nc::new_cli()? };
    let stdplane = unsafe { nc.stdplane() };
    stdplane.putstr("\nhello world!\n")?;
    nc.render()?;
    unsafe { nc.stop()? }; // always stop before exiting
    Ok(())
}

Notes on the Rust API

The Drop trait is not implemented for any wrapping type in this library over structures created by the underlying C library.

This means you still have to manually call the stop() method for Nc and NcDirect objects, and the destroy() method for the rest of types that allocate, (like NcPlane, NcMenu…) at the end of their scope.

But they do implement methods and use NcResult as the return type, for handling errors in the way we are used to in Rust.

For the types that don’t allocate, most are based on primitives like i32, u32, u64… without a name in the C library. In Rust they are type aliased for the C API (e.g.: NcChannel_u32, NcLogLevel_i32, NcStyle_u16…), to leverage type checking. And for the Rust API they are wrapped as unit structs or enums, with associated methods and constants (e.g. NcChannel, NcLogLevel, NcStyle…).

Several methods are declared unsafe when they have addittional contracts to manually upheld in order to avoid UB.

even more like Rust

The WIP sister crate notcurses will eventually offer a closer to Rust, higher-level, safer, and simpler API, and make it easier to interoperate with the rest of the Rust ecosystem.

Like C

You can access the imported, or reimplemented C API functions directly, and use it in a very similar way as the C library is used.

It requires more use of unsafe, since it has less safer abstractions.

Error handling is done this way by checking the returned NcResult_i32, or in case of receiving a pointer, by comparing it to null_mut().

Example

use core::ptr::{null, null_mut};
use std::process::exit;

use libnotcurses_sys::c_api::*;

fn main() {
    let options = ffi::notcurses_options {
        termtype: null(),
        loglevel: 0,
        margin_t: 0,
        margin_r: 0,
        margin_b: 0,
        margin_l: 0,
        flags: NCOPTION_CLI_MODE,
    };

    unsafe {
        let nc = notcurses_init(&options, null_mut());
        if nc.is_null() {
            exit(1);
        }
        let plane = notcurses_stdplane(nc);
        let cols = ncplane_putstr(&mut *plane, "\nhello world!\n");

        if cols < NCRESULT_OK {
            notcurses_stop(nc);
            exit(cols.abs());
        }
        if notcurses_render(&mut *nc) < NCRESULT_OK {
            exit(2);
        }
        if notcurses_stop(nc) < NCRESULT_OK {
            exit(3);
        }
    }
}

The notcurses C API docs

Modules

  • c_api
    The C API, including structs, constants, functions and type aliases.
  • widgets
    The notcurses widgets.

Macros

Structs

Enums

Type Definitions