# netcdf
[](https://docs.rs/netcdf)

[](https://crates.io/crates/netcdf)
[](https://crates.io/crates/netcdf)
[](https://codecov.io/gh/georust/netcdf)

Medium-level [netCDF](http://www.unidata.ucar.edu/software/netcdf/) bindings for Rust, allowing easy reading and writing of array-like structures to a file.
netCDF can read and write `hdf5` files, which is a commonly used file format in scientific computing.
## Status
Supported:
* Variables
* Normal Dimensions
* Attributes
* Subgroups
* Open/Append/Create modes
* Reading from memory
* Unlimited dimensions
* String variables
* User defined types (variable length, enum, compound, opaque)
Not (yet) supported:
* Nested user defined types
* Writing using memory-mapped file
All variable data is read into a contiguous buffer, or into an [ndarray](https://github.com/rust-ndarray/rust-ndarray) if the `ndarray` feature is activated.
## Building
This crate depends on `libnetcdf`, but a static build from source is also supported, which can be enabled using the `static` feature.
The crate is built on several platforms using github actions, and is currently known to build form from source on all major platforms (linux, macos, windows (gnu+msvc)), and through the package installers `conda` and `apt`.
If during compilation there is an error in building the `hdf5` crate, consider using the `static` feature which will include a compatible version of both `netcdf` and `hdf5`. This is likely to be an issue [upstream](https://github.com/aldanor/hdf5-rust/issues/262).
### Building without `libnetcdf` or building statically
1. `git clone https://github.com/georust/netcdf`
2. `git submodule update --init --recursive`
3. `cargo build --features static`
## Documentation
Some examples of usage can be found in the [tests/lib.rs](netcdf/tests/lib.rs) file. The documentation can also be generated using `cargo doc`.
## Thread safety
The `netcdf` crate is thread-safe, although the `netcdf-c` library is not itself threadsafe. To render a safe interface, a global mutex is used to serialize access to the underlying library. Consider using a non threadsafe version of `hdf5` to avoid double locking (performance consideration).
Use of `netcdf-sys` is not thread-safe. Users of this library must take care that calls do not interfere with simultaneous use of e.g. `netcdf`. Using the `hdf5-sys` library could also pose a problem, as this library is used throughout `netCDF-c` and internal state may be disrupted.
## License
Licensed under either of
* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
* MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
at your option.
### Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any
additional terms or conditions.