# jnr-ffi

**Repository Path**: openQlearn/jnr-ffi

## Basic Information

- **Project Name**: jnr-ffi
- **Description**: github 上 jnr-ffi
- **Primary Language**: Unknown
- **License**: Apache-2.0
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2021-04-13
- **Last Updated**: 2024-06-21

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

jnr-ffi [![Build Status](https://travis-ci.org/jnr/jnr-ffi.svg)](https://travis-ci.org/jnr/jnr-ffi)
======

[jnr-ffi](https://github.com/jnr/jnr-ffi) is a Java library for loading native libraries without writing JNI code by hand, or using tools such as SWIG.

Example
------

```java
package helloworld;

import jnr.ffi.LibraryLoader;

public class HelloWorld {
    public static interface LibC {
        int puts(String s);
    }

    public static void main(String[] args) {
        LibC libc = LibraryLoader.create(LibC.class).load("c");

        libc.puts("Hello, World");
    }
}
```

Supported Types
------

All Java primitives are mapped simply to the equivalent C types.

* `byte` - 8 bit signed integer
* `short` - 16 bit signed integer
* `int` - 32 bit signed integer
* `long` - natural long (i.e. 32 bits wide on 32-bit systems, 64 bits wide on 64-bit systems)
* `float` - 32 bit float
* `double` - 64 bit float

The width and/or signed-ness of these basic types can be specified using one of the type alias annotations.
 e.g.

```c
// Use the correct width for the result from getpid(3)
@pid_t long getpid();

// read(2) returns a signed long result, and its length parameter is an unsigned long
@ssize_t long read(int fd, Pointer data, @size_t long len);
```


In addition, the following Java types are mapped to a C pointer

* String - equivalent to `const char *`
* Pointer - equivalent to `void *`
* Buffer - equivalent to `void *`