---
title: capi (v2.4)
description: API reference for qiskit.capi in qiskit v2.4
source: https://eu-de.quantum.cloud.ibm.com/docs/en/api/qiskit/2.4/capi
---

# C API interface from Python

`qiskit.capi`

This module provides Python-space interactions with Qiskit’s public C API.

For documentation on the C API itself, see [Qiskit C API](/docs/api/qiskit-c/).

## Build-system interaction

The Python package [`qiskit`](/docs/api/qiskit/2.4/index#module-qiskit "qiskit") contains all of the Qiskit C API header files, and a compiled shared-object library that includes all of the C-API functions. You can access the locations of these two objects with the functions [`get_include()`](#qiskit.capi.get_include "qiskit.capi.get_include") and [`get_lib()`](#qiskit.capi.get_lib "qiskit.capi.get_lib") respectively.

> **Warning**
>
> You typically *should not* link directly against the output of [`get_lib()`](#qiskit.capi.get_lib "qiskit.capi.get_lib"), unless you know what you are doing. In particular, directly linking against this object is not a safe way to build a distributable Python extension module that uses Qiskit’s C API.
>
> However, if you understand all the caveats of direct linking, you can use the function to get the location of the library.

### get\_include

`qiskit.capi.get_include()`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.4/qiskit/capi/__init__.py#L51-L69)

Get the directory containing the `qiskit.h` C header file and the internal `qiskit/*.h` auxiliary files.

When using Qiskit as a build dependency, you typically want to include this directory on the include search path of your compiler, such as:

```bash
qiskit_include=$(python -c 'import qiskit.capi; print(qiskit.capi.get_include())')
gcc -I "$qiskit_include" my_bin.c -o my_bin
```

The location of this directory within the Qiskit package data is not fixed, and may change between Qiskit versions. You should always use this function to retrieve the directory.

**Returns**

an absolute path to the package include-files directory.

**Return type**

[str](https://docs.python.org/3/library/stdtypes.html#str)

### get\_lib

`qiskit.capi.get_lib()`

[GitHub](https://github.com/Qiskit/qiskit/tree/stable/2.4/qiskit/capi/__init__.py#L72-L90)

Get the path to a shared-object library that contains all the C-API exported symbols.

> **Warning**
>
> You typically *should not* link directly against this object. In particular, directly linking against this object is not a safe way to build a Python extension module that uses Qiskit’s C API.

You can, if you choose, use [`ctypes`](https://docs.python.org/3/library/ctypes.html#module-ctypes) to access the C API symbols contained in this object, though beware that the C-API types declared in the header file are not interchangeable with the Python objects that correspond to them.

The location and name of this file within the Qiskit package data is not fixed, and may change between Qiskit versions.

**Returns**

an absolute path to the shared-object library containing the C-API exported symbols.

**Return type**

[str](https://docs.python.org/3/library/stdtypes.html#str)