| OpenCV 4.3.0 Open Source Computer Vision

Classes | Macros | Enumerations
Low-level API for external libraries / plugins
Core functionality » Hardware Acceleration Layer

## Classes
struct | OpenCV_API_Header

## Macros
#define | CV_API_CALL
| calling convention (including callbacks) More...

## Enumerations
enum | CvResult { CV_ERROR_FAIL = -1, CV_ERROR_OK = 0 }

## Detailed Description

API for OpenCV external plugins:

- HAL accelerators
- VideoIO camera backends / decoders / encoders
- Imgcodecs encoders / decoders

Plugins are usually built separately or before OpenCV (OpenCV can depend on them - like HAL libraries).

Using this approach OpenCV provides some basic low level functionality for external plugins.

Note
  Preview only (no backward compatibility)

## Macro Definition Documentation

## ◆ CV_API_CALL

#define CV_API_CALL

`#include <opencv2/core/llapi/llapi.h>`

calling convention (including callbacks)

## Enumeration Type Documentation

## ◆ CvResult

enum CvResult

`#include <opencv2/core/llapi/llapi.h>`

Enumerator
CV_ERROR_FAIL | Some error occurred (TODO Require to fill exception information)
CV_ERROR_OK | No error.