Package jnr.ffi.byref

Class NativeLongByReference

java.lang.Object

java.lang.Number

jnr.ffi.byref.AbstractNumberReference<NativeLong>

jnr.ffi.byref.NativeLongByReference

All Implemented Interfaces:

java.io.Serializable, ByReference<NativeLong>

public final class NativeLongByReference
extends AbstractNumberReference<NativeLong>

NativeLongByReference is used when the address of a primitive C long must be passed as a parameter to a function.

For example, the following C code,

 
 extern void get_a(long * ap);

 long foo(void) {
     long 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 NativeLongByReference ap);
 }
 
 

and used like this

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

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
NativeLongByReference()	Creates a new reference to a native long value initialized to zero.
NativeLongByReference(long value)	Creates a new reference to a native long value
NativeLongByReference(NativeLong value)	Creates a new reference to a native long value

Method Summary

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

Methods inherited from class jnr.ffi.byref.AbstractNumberReference

byteValue, checkNull, doubleValue, floatValue, getValue, intValue, longValue, shortValue

Methods inherited from class java.lang.Object

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

Constructor Detail

NativeLongByReference

public NativeLongByReference()

Creates a new reference to a native long value initialized to zero.

NativeLongByReference

public NativeLongByReference(NativeLong value)

Creates a new reference to a native long value

Parameters:

value - the initial native value

NativeLongByReference

public NativeLongByReference(long value)

Creates a new reference to a native long value

Parameters:

value - the initial native value

Method Detail

toNative

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

Copies the long value to native memory

Parameters:

runtime - the current runtime.

memory - the native memory buffer.

offset - the memory offset.

fromNative

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

Copies the long value from native memory

Parameters:

runtime - the current runtime.

memory - the native memory buffer.

offset - the memory offset.

nativeSize

public final int nativeSize(Runtime runtime)

Gets the native size of type of reference in bytes.

Parameters:

runtime - the current runtime.

Returns:

the size of a byte in bytes