C API reference

metatensor offers a C API that can be called from any language able to call C functions (in particular, this includes Python, Fortran with iso_c_env, C++, and most languages used nowadays). Convenient wrappers of the C API are also provided for Python users.

The C API is implemented in Rust. You can use these functions in your own code by installing the corresponding shared library and header, and then including metatensor.h and linking with -lmetatensor. Alternatively, we provide a cmake package config file, allowing you to do use metatensor like this (after installation):

cmake_minimum_required(VERSION 3.16)
project(my-project C)


# add executables/libraries
add_executable(my-exe exe-source.c)
add_library(my-lib lib-source.c)

# Link to metatensor, this makes the header accessible and link to the right
# libraries.
# The `metatensor` target will be an alias for `metatensor::shared`
# or `metatensor::static` depending how you've installed the code.
target_link_libraries(my-exe metatensor)
target_link_libraries(my-lib metatensor)

# alternatively, you can explicitly use the static or shared build of
# metatensor. Unless you have a very specific need for a static build, we
# recommend using the shared version of metatensor: this will allow to pass
# data from your code to any other code using metatensor.

# target_link_libraries(my-exe metatensor::shared)
# target_link_libraries(my-exe metatensor::static)

The functions and types provided in metatensor.h can be grouped in five main groups: