# 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:
* [GMP] for integers and rational numbers,
* [MPFR] for floating-point numbers, and
* [MPC] for complex numbers.
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.
## What’s new
### Version 1.1.6 news (2018-05-29)
* A fix was included to automatically work around
[Rust issue #47048][47048] (which only affects MinGW).
[47048]: https://github.com/rust-lang/rust/issues/47048
### Version 1.1.5 news (2018-05-02)
* MPFR was updated from version 4.0.1 to version 4.0.1-p6.
### Version 1.1.4 news (2018-04-23)
* Missing functions taking [`*mut FILE`][`libc::FILE`] arguments were
added to the [`gmp`], [`mpfr`] and [`mpc`] modules.
[`libc::FILE`]: https://docs.rs/libc/^0.2/libc/enum.FILE.html
### Other releases
Details on other releases can be found in [*RELEASES.md*].
## Basic features
This crate contains three modules:
* [`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 [Rug][rug crate], a crate
which provides big integer and floating-point numbers. Its main
features are
* bignum [integers][`Integer`] with arbitrary precision,
* bignum [rational numbers][`Rational`] with arbitrary precision,
* multi-precision [floating-point numbers][`Float`] with correct
rounding, and
* multi-precision [complex numbers][`Complex`] with 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][sys crate]. To use
gmp-mpfr-sys in your crate, add it as a dependency inside
[*Cargo.toml*]:
```toml
[dependencies]
gmp-mpfr-sys = "1.1"
```
You also need to declare it by adding this to your crate root (usually
*lib.rs* or *main.rs*):
```rust
extern crate gmp_mpfr_sys;
```
This crate required rustc version 1.13.0 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 `"~1.1"` instead of version `"1.1"` 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*]:
```toml
[dependencies.gmp-mpfr-sys]
version = "1.1"
default-features = false
features = ["mpfr"]
```
Here only the `mpfr` feature is selected.
## 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:
```sh
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:
```sh
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][msys].
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.
```sh
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.
3. Build the crate using `cargo`.
[*Cargo.toml*]: https://doc.rust-lang.org/cargo/guide/dependencies.html
[*RELEASES.md*]: https://gitlab.com/tspiteri/gmp-mpfr-sys/blob/master/RELEASES.md
[GMP]: https://gmplib.org/
[GNU GPL]: https://www.gnu.org/licenses/gpl-3.0.html
[GNU LGPL]: https://www.gnu.org/licenses/lgpl-3.0.en.html
[GNU]: https://www.gnu.org/
[MPC]: http://www.multiprecision.org/mpc/
[MPFR]: http://www.mpfr.org/
[`Complex`]: https://docs.rs/rug/*/rug/struct.Complex.html
[`Float`]: https://docs.rs/rug/*/rug/struct.Float.html
[`Integer`]: https://docs.rs/rug/*/rug/struct.Integer.html
[`MPFR_RNDN`]: https://tspiteri.gitlab.io/gmp-mpfr-sys/mpfr/MPFR-Basics.html#Rounding-Modes
[`Rational`]: https://docs.rs/rug/*/rug/struct.Rational.html
[`enum MPFR_RND_T`]: https://tspiteri.gitlab.io/gmp-mpfr-sys/mpfr/MPFR-Basics.html#index-mpfr_005frnd_005ft
[`gmp::mpf_t`]: https://docs.rs/gmp-mpfr-sys/~1.1/gmp_mpfr_sys/gmp/struct.mpf_t.html
[`gmp::mpq_t`]: https://docs.rs/gmp-mpfr-sys/~1.1/gmp_mpfr_sys/gmp/struct.mpq_t.html
[`gmp::mpz_init`]: https://docs.rs/gmp-mpfr-sys/~1.1/gmp_mpfr_sys/gmp/fn.mpz_init.html
[`gmp::mpz_t`]: https://docs.rs/gmp-mpfr-sys/~1.1/gmp_mpfr_sys/gmp/struct.mpz_t.html
[`gmp::randstate_t`]: https://docs.rs/gmp-mpfr-sys/~1.1/gmp_mpfr_sys/gmp/struct.randstate_t.html
[`gmp::set_memory_functions`]: https://docs.rs/gmp-mpfr-sys/~1.1/gmp_mpfr_sys/gmp/fn.set_memory_functions.html
[`gmp`]: https://docs.rs/gmp-mpfr-sys/~1.1/gmp_mpfr_sys/gmp/index.html
[`mp_set_memory_functions`]: https://tspiteri.gitlab.io/gmp-mpfr-sys/gmp/Custom-Allocation.html#index-mp_005fset_005fmemory_005ffunctions
[`mpc::mpc_t`]: https://docs.rs/gmp-mpfr-sys/~1.1/gmp_mpfr_sys/mpc/struct.mpc_t.html
[`mpc`]: https://docs.rs/gmp-mpfr-sys/~1.1/gmp_mpfr_sys/mpc/index.html
[`mpfr::mpfr_t`]: https://docs.rs/gmp-mpfr-sys/~1.1/gmp_mpfr_sys/mpfr/struct.mpfr_t.html
[`mpfr::rnd_t::RNDN`]: https://docs.rs/gmp-mpfr-sys/~1.1/gmp_mpfr_sys/mpfr/enum.rnd_t.html#variant.RNDN
[`mpfr`]: https://docs.rs/gmp-mpfr-sys/~1.1/gmp_mpfr_sys/mpfr/index.html
[`mpz_init`]: https://tspiteri.gitlab.io/gmp-mpfr-sys/gmp/Integer-Functions.html#index-mpz_005finit
[msys]: https://msys2.github.io/
[rug crate]: https://crates.io/crates/rug
[sys crate]: https://crates.io/crates/gmp-mpfr-sys