Crate gmp_mpfr_sys[−][src]

Rust low-level bindings for GMP, MPFR and MPC

The gmp-mpfr-sys crate provides Rust FFI bindings to the following GNU arbitrary-precision libraries:

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

The gmp-mpfr-sys 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 features

This crate contains three modules:

The versions provided by this crate release are GMP version 6.2.0, MPFR version 4.1.0, and MPC version 1.1.0.

If you want a high-level API, consider using Rug, a crate which provides integers and floating-point numbers with arbitrary precision and correct rounding:

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.

Types

Unlike in the C libraries, the types gmp::mpz_t, gmp::mpq_t, gmp::mpf_t, gmp::randstate_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.

Using gmp-mpfr-sys

The gmp-mpfr-sys crate is available on crates.io. To use gmp-mpfr-sys in your crate, add it as a dependency inside Cargo.toml:

[dependencies]
gmp-mpfr-sys = "1.3"

This crate required rustc version 1.37.0 or later.

If the C libraries have a major version bump with some deprecated functions removed, but no features are removed in the Rust bindings, then gmp-mpfr-sys will have a minor version bump rather than a major version bump. This allows more compatiblity across crates that use the Rust bindings but do not use the C libraries directly.

If on the other hand a dependent crate makes use of internal implementation details, or includes a C library that directly uses the header (.h) and library (.a) files built using C, it can be a good idea to depend on version "~1.3" instead of version "1.3" in order to ensure backwards compatibility at the C level as well.

Optional features

The gmp-mpfr-sys crate has two optional features:

  1. mpfr, enabled by default. Required to include the MPFR library.
  2. mpc, enabled by default. Required to include the MPC library. This feature requires the mpfr feature.

The GMP library is always included.

The two optional features are enabled by default; to use features selectively, you can add the dependency like this to Cargo.toml:

[dependencies.gmp-mpfr-sys]
version = "1.3"
default-features = false
features = ["mpfr"]

Here only the mpfr feature is selected.

Experimental optional features

It is not considered a breaking change if experimental features are removed. The removal of experimental features would however require a minor version bump.

Experimental features may also not work on all platforms.

There are two experimental feature:

  1. use-system-libs, disabled by default. Using this feature, the system libraries for GMP, and MPFR and MPC if enabled, will be used instead of building them from source. The versions must be compatible with the versions provided by the crate.
  2. force-cross, disabled by default. Without this feature, the build will fail if cross compilation is detected, because cross compilation is not tested or supported and can lead to silent failures that are hard to debug, especially if this crate is an indirect dependency. As an exception, cross compiling from x86_64 to i686 does not need this feature.

Metadata

The gmp-mpfr-sys crate passes some metadata to its dependents:

  1. DEP_GMP_LIMB_BITS contains the number of bits per limb, which is 32 or 64.
  2. DEP_GMP_OUT_DIR contains the path of a directory that contains two subdirectories: the first subdirectory is named lib and contains the generated library (.a) files, and the second subdirectory is named include and contains the corresponding header (.h) files.
  3. DEP_GMP_LIB_DIR contains the path of the lib subdirectory of the DEP_GMP_OUT_DIR directory.
  4. DEP_GMP_INCLUDE_DIR contains the path of the include subdirectory of the DEP_GMP_OUT_DIR directory.

A dependent crate can use these environment variables in its build script.

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. To install them, run the following command in a terminal:

xcode-select --install

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

  2. Change to the crate directory.

  3. Build the crate using cargo.

Cross compilation

While some cross compilation is possible, it is not tested automatically, and may not work. Merge requests that improve cross compilation are accepted.

From the next minor version 1.3 onwards, the experimental feature force-cross must be enabled for cross compilation. There is one case which is allowed even without the feature: when the only difference between host and target is that the host is x86_64 and the target is i686.

Caching the built C libraries

Building the C libraries can take some time. In order to save compilation time, the built libraries are cached in the user’s cache directory as follows:

To use a different directory, you can set the environment variable GMP_MPFR_SYS_CACHE to the desired cache directory. Setting the GMP_MPFR_SYS_CACHE variable to an empty string will disable caching.

Modules

C

This module is a place-holder for documentation; do not use it in code.

gmp

Function and type bindings for the GMP library.

mpfr

Function and type bindings for the MPFR library.

Macros

MPFR_DECL_INIT

See: MPFR_DECL_INIT

mpfr_round_nearest_away

See: mpfr_round_nearest_away