ByReference (jnr-ffi 2.2.7 API)

All Known Implementing Classes:

AbstractNumberReference, AbstractReference, AddressByReference, ByteByReference, DoubleByReference, FloatByReference, IntByReference, LongLongByReference, NativeLongByReference, NumberByReference, PointerByReference, ShortByReference
```
public interface ByReference<T>
```
A ByReference subclass is used when a primitive parameter must be passed by-reference.
For example, the following C code,
```
 

 extern void get_a(int * ap);

 int foo(void) {
     int a;
     // pass a reference to 'a' so get_a() can fill it out
     get_a(&a);

     return a;
 }
  
 
```
Would be declared in java as
```
 

 interface Lib {
     void get_a(@Out IntByReference ap);
 }

 
 
```
and used like this
```
 

 IntByReference ap = new IntByReference();
 lib.get_a(ap);
 System.out.printf("a from lib=%d\n", a.getValue());

 
 
```

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`fromNative(Runtime runtime, Pointer memory, long offset)`	Copies the java value from native memory
`T`	`getValue()`
`int`	`nativeSize(Runtime runtime)`	Gets the size of the native buffer required to store the value
`void`	`toNative(Runtime runtime, Pointer memory, long offset)`	Copies the java value to native memory

- Method Detail
  - nativeSize
```
int nativeSize(Runtime runtime)
```
    Gets the size of the native buffer required to store the value
    
    Parameters:
    
    runtime - The current runtime.
    
    Returns:
    
    the size in bytes of the native type
  - toNative
```
void toNative(Runtime runtime,
              Pointer memory,
              long offset)
```
    Copies the java value to native memory
    
    Parameters:
    
    runtime - The current runtime.
    
    memory - The native memory buffer.
    
    offset - The offset of the field.
  - fromNative
```
void fromNative(Runtime runtime,
                Pointer memory,
                long offset)
```
    Copies the java value from native memory
    
    Parameters:
    
    runtime - The current runtime.
    
    memory - the native memory buffer.
    
    offset - The offset of the field.
  - getValue
```
T getValue()
```