Crate gmp_mpfr_sys [] [src]

Rust low-level bindings for GMP, MPFR and MPC

The gmp-mpfr-sys crate provides Rust FFI bindings for:

  • the GNU Multiple Precision Arithmetic Library (GMP) version 6.1.2, a library for arbitrary precision arithmetic,
  • the GNU MPFR Library version 4.0.0, a library for multiple-precision floating-point computations with correct rounding, and
  • GNU MPC version 1.1.0, a library for the arithmetic of complex numbers with arbitrarily high precision and correct rounding.

The source of the three libraries is included in the package.

This crate is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. See the full text of the GNU LGPL and GNU GPL for details.

Basic use

This crate required rustc version 1.13.0.

This crate provides a low-level interface to GMP, MPFR and MPC in three modules. The documentation of the three modules contains links for each function, constant and type into the respective documentation of GMP, MPFR and MPC libraries. The three modules of this crate are:

  • gmp provides external FFI bindings to GMP.
  • mpfr provides external FFI bindings to MPFR.
  • mpc provides external FFI bindings to MPC.

If you want a high-level API, consider using the rug crate, which provides big integer and floating-point numbers. Its main features are:


Name prefixes

Since modules and enumerated types provide namespacing, most prefixes in the C names are removed. However, when the prefix is not a whole word it is not removed, for example mp_set_memory_functions() becomes gmp::set_memory_functions(), but mpz_init() becomes gmp::mpz_init() not gmp::z_init(), and MPFR_RNDN in enum MPFR_RND_T becomes mpfr::rnd_t::RNDN not mpfr::rnd_t::N. Also, the types mpfr::mpfr_t and mpc::mpc_t are not shortened to mpfr::t or mpc::t.


Unlike in the C libraries, the types gmp::mpz_t, gmp::mpq_t, gmp::mpf_t, gmp::rand_state_t, mpfr::mpfr_t and mpc::mpc_t are defined directly as structs, not as single-element arrays.

Undocumented or obsolete functions

The bindings do not cover undocumented or obsolete functions and macros.


To use gmp-mpfr-sys in your crate, add extern crate gmp_mpfr_sys; to the crate root and add gmp-mpfr-sys as a dependency in Cargo.toml:

gmp-mpfr-sys = "1.1.0"

Optional features

The gmp-mpfr-sys crate has two optional features mpfr and mpc to include the MPFR and MPC libraries respectively. The GMP library is always included. The optional features are enabled by default; to disable them add this to Cargo.toml:

version = "1.1.0"
default-features = false

To use features selectively, you can add this to Cargo.toml:

version = "1.1.0"
default-features = false
# Pick which features to use
features = ["mpfr"]

Note that the the mpc feature depends on, and will enable, the mpfr feature.

Building on GNU/Linux

To build on GNU/Linux, simply make sure you have diffutils, gcc, make and m4 installed on your system. For example on Fedora:

sudo dnf install diffutils gcc make m4

Building on macOS

To build on macOS, you need the command-line developer tools. An easy way to install them is to start building the crate using cargo build. If the tools are not installed yet, a popup should appear which should help you install them.

Building on Windows

You can build on Windows with the Rust GNU toolchain and an up-to-date MSYS2 installation. Some steps for a 64-bit environment are listed below. (32-bit: Changes for a 32-bit environment are written in brackets like this comment.)

To install MSYS2:

  1. Install MSYS2 using the installer.

  2. Launch the MSYS2 MinGW 64-bit terminal from the start menu. (32-bit: Launch the MSYS2 MinGW 32-bit terminal instead.)

  3. Install the required tools.

    pacman -S pacman-mirrors
    pacman -S diffutils make mingw-w64-x86_64-gcc

    (32-bit: Install mingw-w64-i686-gcc instead of mingw-w64-x86_64-gcc.)

Then, to build a crate with a dependency on this crate:

  1. Launch the MSYS MinGW 64-bit terminal from the start menu. (32-bit: Launch the MSYS2 MinGW 32-bit terminal instead.)

  2. Change to the crate directory.

    Note that building the GMP, MPFR and MPC libraries in MSYS with absolute paths does not work very well, so relative paths are used. If your crate is inside C:\msys64 and the .cargo directory is outside C:\msys64, this will not work. Please move your crate to the same side of C:\msys64 as .cargo.

  3. Build the crate using cargo.



Function and type bindings for the GMP library.


Function and type bindings for the MPC library.


Function and type bindings for the MPFR library.



See: mpfr_round_nearest_away