Package jnr.ffi.byref

Class NativeLongByReference

All Implemented Interfaces:
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:
  • Constructor Details

    • 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 Details

    • 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