Package jnr.ffi.byref

Class AddressByReference

java.lang.Object

jnr.ffi.byref.AbstractReference<Address>

jnr.ffi.byref.AddressByReference

All Implemented Interfaces:

ByReference<Address>

public final class AddressByReference
extends AbstractReference<Address>

AddressByReference is used when the address of a primitive pointer value must be passed as a parameter to a function.

For example, the following C code,

 

 extern void get_a(void** ap);

 void* foo(void) {
     void* 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 AddressByReference ap);
 }

 
 

and used like this

 

 AddressByReference ap = new AddressByReference();
 lib.get_a(ap);
 System.out.println("a from lib=" + a.getValue());

 
 

Constructor Summary

Constructors

Constructor	Description
AddressByReference()	Creates a new reference to an integer value
AddressByReference(Address value)	Creates a new reference to an address value

Method Summary

Modifier and Type	Method	Description
void	fromNative(Runtime runtime, Pointer memory, long offset)	Copies the address value from native memory
int	nativeSize(Runtime runtime)	Gets the native size of type of reference
void	toNative(Runtime runtime, Pointer memory, long offset)	Copies the address value to native memory

Methods inherited from class jnr.ffi.byref.AbstractReference

checkNull, getValue

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AddressByReference

public AddressByReference()

Creates a new reference to an integer value

AddressByReference

public AddressByReference(Address value)

Creates a new reference to an address value

Parameters:

value - the initial native value

Method Detail

toNative

public void toNative(Runtime runtime,
                     Pointer memory,
                     long offset)

Copies the address value to native memory

Parameters:

runtime - The current runtime.

memory - The native memory buffer

offset - The offset.

fromNative

public void fromNative(Runtime runtime,
                       Pointer memory,
                       long offset)

Copies the address value from native memory

Parameters:

runtime - The current runtime.

memory - The native memory buffer.

offset - The offset.

nativeSize

public int nativeSize(Runtime runtime)

Gets the native size of type of reference

Parameters:

runtime - The current runtime.

Returns:

The size of the native type this reference points to