JNR 2023-06-06 · com.kenai.jffi.Library

Modifier and Type	Class and Description
private static class	Library.DefaultLibrary A handle to the current process

Field Summary

Modifier and Type	Field and Description
private static final Map<String, WeakReference<Library>>	cache A cache of opened libraries
private volatile int	disposed Indicates whether this library has been disposed of.
private final Foreign	foreign A handle to the foreign interface to keep it alive as long as this object is alive
public static final int	GLOBAL All symbols in the library are made available to other libraries
private final long	handle The native dl/LoadLibrary handle
private static final ThreadLocal<String>	lastError Stores the last error returned by a dlopen or dlsym call
public static final int	LAZY Perform lazy binding.
public static final int	LOCAL Symbols in this library are not made available to other libraries
private static final Object	lock A lock used to serialize all dlopen/dlsym calls
private final String	name The name of this `Library`
public static final int	NOW Resolve all symbols when loading the library
private static final AtomicIntegerFieldUpdater<Library>	UPDATER

Constructor Summary

Access	Constructor and Description
private	Library(Foreign foreign, String name, long address)

Method Summary

Modifier and Type	Method and Description
private static long	Returns: The native handle for the opened library, or 0 if it failed to open. dlopen(Foreign foreign, String The name of the library to open name, int The flags to pass to dlopen flags) Internal wrapper around dlopen.
protected void	finalize() Overrides java.lang.Object.finalize. Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
public static final Library	Returns: A `Library` instance representing the named library, or `null` if the library could not be opened. getCachedInstance(String The name or path of the library to open. name, int The library flags (e.g. `LAZY, NOW, LOCAL, GLOBAL`) flags) Gets a handle for the named library.
public static final Library	Returns: A `Library` instance representing the default library. getDefault() Gets a handle to the default library.
public static final String	Returns: A `String` describing the last error. getLastError() Gets the current error string from dlopen/LoadLibrary.
public final long	Returns: The address of the symbol within the current address space. getSymbolAddress(String The name of the symbol to locate. name) Gets the address of a symbol within the `Library`.
public static final Library	Returns: A `Library` instance representing the named library, or null if the library cannot be opened. openLibrary(String The name or path of the library to open. name, int The library flags (e.g. `LAZY, NOW, LOCAL, GLOBAL`) flags) Gets a handle for the named library Note This will not cache the instance, nor will it return a cached instance.

Inherited from java.lang.Object:: clone equals getClass hashCode notify notifyAll toString wait wait wait

Field Detail

cache	back to summary
private static final Map<String, WeakReference<Library>> cache A cache of opened libraries

disposed	back to summary
private volatile int disposed Indicates whether this library has been disposed of.

foreign	back to summary
private final Foreign foreign A handle to the foreign interface to keep it alive as long as this object is alive

GLOBAL	back to summary
public static final int GLOBAL All symbols in the library are made available to other libraries

handle	back to summary
private final long handle The native dl/LoadLibrary handle

lastError	back to summary
private static final ThreadLocal<String> lastError Stores the last error returned by a dlopen or dlsym call

LAZY	back to summary
public static final int LAZY Perform lazy binding. Only resolve symbols as needed

LOCAL	back to summary
public static final int LOCAL Symbols in this library are not made available to other libraries

lock	back to summary
private static final Object lock A lock used to serialize all dlopen/dlsym calls

name	back to summary
private final String name The name of this `Library`

NOW	back to summary
public static final int NOW Resolve all symbols when loading the library

UPDATER	back to summary
private static final AtomicIntegerFieldUpdater<Library> UPDATER

Constructor Detail

Library	back to summary
private Library(Foreign foreign, String name, long address)

Method Detail

dlopen	back to summary
private static long dlopen(Foreign foreign, String name, int flags) Internal wrapper around dlopen. If the library open fails, then this stores the native error in a thread local variable for later retrieval. Parameters name:String The name of the library to open flags:int The flags to pass to dlopen Returns:long The native handle for the opened library, or 0 if it failed to open.

dlopen

back to summary

private static long dlopen(Foreign foreign, String name, int flags)

Internal wrapper around dlopen. If the library open fails, then this stores the native error in a thread local variable for later retrieval.

Parameters

name:String: The name of the library to open
flags:int: The flags to pass to dlopen

Returns:long

The native handle for the opened library, or 0 if it failed to open.

finalize back to summary

finalize	back to summary
protected void finalize() throws Throwable Overrides java.lang.Object.finalize. Doc from java.lang.Object.finalize. Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. A subclass overrides the `finalize` method to dispose of system resources or to perform other cleanup. When running in a Java virtual machine in which finalization has been disabled or removed, the garbage collector will never call `finalize()`. In a Java virtual machine in which finalization is enabled, the garbage collector might call `finalize` only after an indefinite delay. The general contract of `finalize` is that it is invoked if and when the Java virtual machine has determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, except as a result of an action taken by the finalization of some other object or class which is ready to be finalized. The `finalize` method may take any action, including making this object available again to other threads; the usual purpose of `finalize`, however, is to perform cleanup actions before the object is irrevocably discarded. For example, the finalize method for an object that represents an input/output connection might perform explicit I/O transactions to break the connection before the object is permanently discarded. The `finalize` method of class `Object` performs no special action; it simply returns normally. Subclasses of `Object` may override this definition. The Java programming language does not guarantee which thread will invoke the `finalize` method for any given object. It is guaranteed, however, that the thread that invokes finalize will not be holding any user-visible synchronization locks when finalize is invoked. If an uncaught exception is thrown by the finalize method, the exception is ignored and finalization of that object terminates. After the `finalize` method has been invoked for an object, no further action is taken until the Java virtual machine has again determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, including possible actions by other objects or classes which are ready to be finalized, at which point the object may be discarded. The `finalize` method is never invoked more than once by a Java virtual machine for any given object. Any exception thrown by the `finalize` method causes the finalization of this object to be halted, but is otherwise ignored. Annotations @Override Exceptions Throwable: the `Exception` raised by this method

protected void finalize() throws Throwable

Overrides java.lang.Object.finalize.

Doc from java.lang.Object.finalize.

Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. A subclass overrides the finalize method to dispose of system resources or to perform other cleanup.

When running in a Java virtual machine in which finalization has been disabled or removed, the garbage collector will never call finalize(). In a Java virtual machine in which finalization is enabled, the garbage collector might call finalize only after an indefinite delay.

The general contract of finalize is that it is invoked if and when the Java virtual machine has determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, except as a result of an action taken by the finalization of some other object or class which is ready to be finalized. The finalize method may take any action, including making this object available again to other threads; the usual purpose of finalize, however, is to perform cleanup actions before the object is irrevocably discarded. For example, the finalize method for an object that represents an input/output connection might perform explicit I/O transactions to break the connection before the object is permanently discarded.

The finalize method of class Object performs no special action; it simply returns normally. Subclasses of Object may override this definition.

The Java programming language does not guarantee which thread will invoke the finalize method for any given object. It is guaranteed, however, that the thread that invokes finalize will not be holding any user-visible synchronization locks when finalize is invoked. If an uncaught exception is thrown by the finalize method, the exception is ignored and finalization of that object terminates.

After the finalize method has been invoked for an object, no further action is taken until the Java virtual machine has again determined that there is no longer any means by which this object can be accessed by any thread that has not yet died, including possible actions by other objects or classes which are ready to be finalized, at which point the object may be discarded.

The finalize method is never invoked more than once by a Java virtual machine for any given object.

Any exception thrown by the finalize method causes the finalization of this object to be halted, but is otherwise ignored.

Annotations

@Override

Exceptions

Throwable:: the Exception raised by this method

getCachedInstance back to summary

getCachedInstance	back to summary
public static final Library getCachedInstance(String name, int flags) Gets a handle for the named library. Parameters name:String The name or path of the library to open. flags:int The library flags (e.g. `LAZY, NOW, LOCAL, GLOBAL`) Returns:Library A `Library` instance representing the named library, or `null` if the library could not be opened.

public static final Library getCachedInstance(String name, int flags)

Gets a handle for the named library.

Parameters

name:String: The name or path of the library to open.
flags:int: The library flags (e.g. LAZY, NOW, LOCAL, GLOBAL)

Returns:Library

A Library instance representing the named library, or null if the library could not be opened.

getDefault back to summary

getDefault	back to summary
public static final Library getDefault() Gets a handle to the default library. Returns:Library A `Library` instance representing the default library.

public static final Library getDefault()

Gets a handle to the default library.

Returns:Library: A Library instance representing the default library.

getLastError back to summary

getLastError	back to summary
public static final String getLastError() Gets the current error string from dlopen/LoadLibrary. Returns:String A `String` describing the last error.

public static final String getLastError()

Gets the current error string from dlopen/LoadLibrary.

Returns:String: A String describing the last error.

getSymbolAddress back to summary

getSymbolAddress	back to summary
public final long getSymbolAddress(String name) Gets the address of a symbol within the `Library`. Parameters name:String The name of the symbol to locate. Returns:long The address of the symbol within the current address space.

public final long getSymbolAddress(String name)

Gets the address of a symbol within the Library.

Parameters

name:String: The name of the symbol to locate.

Returns:long

The address of the symbol within the current address space.

openLibrary back to summary

openLibrary	back to summary
public static final Library openLibrary(String name, int flags) Gets a handle for the named library Note This will not cache the instance, nor will it return a cached instance. Only use when you really need a new handle for the library. Parameters name:String The name or path of the library to open. flags:int The library flags (e.g. `LAZY, NOW, LOCAL, GLOBAL`) Returns:Library A `Library` instance representing the named library, or null if the library cannot be opened.

public static final Library openLibrary(String name, int flags)

Gets a handle for the named library

Note

This will not cache the instance, nor will it return a cached instance. Only use when you really need a new handle for the library.

Parameters

name:String: The name or path of the library to open.
flags:int: The library flags (e.g. LAZY, NOW, LOCAL, GLOBAL)

Returns:Library

A Library instance representing the named library, or null if the library cannot be opened.

public final Class Library

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary

Field Detail

Constructor Detail

Method Detail

private final Class Library.DefaultLibrary

Field Summary

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Constructor Detail