Crate libR_sys

source ·
Expand description

A low-level libR binding library which is kept deliberately minimal.

In particular, it has no external dependencies other that libR installed on the target.

Synopsis

The libR-sys crate is a low level bindgen wrapper for the R programming language. The intention is to allow one or more extension mechanisms to be implemented for rust.

Effort to make the extension libraries platform-independent can be concentrated here.

Examples

use libR_sys::{Rf_initialize_R, R_CStackLimit, setup_Rmainloop};
use std::os::raw;

unsafe {
  std::env::set_var("R_HOME", "/usr/lib/R");
  let arg0 = "R\0".as_ptr() as *mut raw::c_char;
  Rf_initialize_R(1, [arg0].as_mut_ptr());
  R_CStackLimit = usize::max_value();
  setup_Rmainloop();
}

Conditional compilation depending on R installation

The libR-sys crate provides these environmental variables that you can use in build.rs:

  • DEP_R_R_VERSION_MAJOR: The major part of the R version (e.g. 4 in version 4.1.0)
  • DEP_R_R_VERSION_MINOR: The minor part of the R version (e.g. 1 in version 4.1.0)
  • DEP_R_R_VERSION_PATCH: The patch part of the R version (e.g. 0 in version 4.1.0)
  • DEP_R_R_VERSION_DEVEL: true if the R is a development version, otherwise false
  • DEP_R_R_VERSION_STRING: The full version string (e.g. R version 4.1.0 (2021-05-18))
  • DEP_R_R_HOME: The R home directory

Example build.rs

ⓘ
use std::env;

fn main() {
    // Set R_HOME envvar, and refer to it on compile time by env!("R_HOME")
    let r_home = env::var("DEP_R_R_HOME").unwrap();
    println!("cargo:rustc-env=R_HOME={}", r_home);

    // Enable cfg setting to conditionally compile a code using a feature
    // available only on newer versions of R
    let major = env::var("DEP_R_R_VERSION_MAJOR").unwrap();
    let minor = env::var("DEP_R_R_VERSION_MINOR").unwrap();
    if &*major >= "4" && &*minor >= "1" {
        println!("cargo:rustc-cfg=use_a_feature");
    }
}

Structs

Constants

Statics

Functions

Type Definitions