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JNA API 4.2.0
com.sun.jna

Class Native

  • All Implemented Interfaces:
    Version


    public final class Native
    extends Object
    implements Version
    Provides generation of invocation plumbing for a defined native library interface. Also provides various utilities for native operations.

    getTypeMapper(java.lang.Class) and getStructureAlignment(java.lang.Class) are provided to avoid having to explicitly pass these parameters to Structures, which would require every Structure which requires custom mapping or alignment to define a constructor and pass parameters to the superclass. To avoid lots of boilerplate, the base Structure constructor figures out these properties based on its enclosing interface.

    Library Loading

    When JNA classes are loaded, the native shared library (jnidispatch) is loaded as well. An attempt is made to load it from the any paths defined in jna.boot.library.path (if defined), then the system library path using System.loadLibrary(java.lang.String), unless jna.nosys=true. If not found, the appropriate library will be extracted from the class path (into a temporary directory if found within a jar file) and loaded from there, unless jna.noclasspath=true. If your system has additional security constraints regarding execution or load of files (SELinux, for example), you should probably install the native library in an accessible location and configure your system accordingly, rather than relying on JNA to extract the library from its own jar file.

    To avoid the automatic unpacking (in situations where you want to force a failure if the JNA native library is not properly installed on the system), set the system property jna.nounpack=true.

    While this class and its corresponding native library are loaded, the system property jna.loaded will be set. The property will be cleared when native support has been unloaded (i.e. the Native class and its underlying native support has been GC'd).

    NOTE: all native functions are provided within this class to ensure that all other JNA-provided classes and objects are GC'd and/or finalized/disposed before this class is disposed and/or removed from memory (most notably Memory and any other class which by default frees its resources in a finalizer).

    Native Library Loading

    Native libraries loaded via loadLibrary(Class) may be found in several locations.
    Author:
    Todd Fast, todd.fast@sun.com, twall@users.sf.net
    See Also:
    Library
    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class and Description
      static interface  Native.ffi_callback 
    • Method Summary

      All Methods Static Methods Concrete Methods Deprecated Methods 
      Modifier and Type Method and Description
      (package private) static void close(long handle)
      Close the given native library.
      (package private) static long createNativeCallback(Callback callback, Method method, Class[] parameterTypes, Class returnType, int callingConvention, int flags, String encoding)
      Create a native trampoline to delegate execution to the Java callback.
      (package private) static boolean deleteLibrary(File lib)
      Remove any automatically unpacked native library.
      static void detach(boolean detach)
      Indicate whether the JVM should detach the current native thread when the current Java code finishes execution.
      static File extractFromResourcePath(String name)
      Attempt to extract a native library from the current resource path, using the current thread context class loader.
      static File extractFromResourcePath(String name, ClassLoader loader)
      Attempt to extract a native library from the resource path using the given class loader.
      static void ffi_call(long cif, long fptr, long resp, long args)
      Make an FFI function call.
      static void ffi_free_closure(long closure) 
      static long ffi_prep_cif(int abi, int nargs, long ffi_return_type, long ffi_types)
      Create a new cif structure.
      static long ffi_prep_closure(long cif, Native.ffi_callback cb) 
      (package private) static Class findDirectMappedClass(Class cls)
      Find the nearest enclosing class with native methods.
      (package private) static Class findEnclosingLibraryClass(Class cls)
      Find the library interface corresponding to the given class.
      (package private) static long findSymbol(long handle, String name) 
      static void free(long ptr)
      Call the real native free
      (package private) static void freeNativeCallback(long ptr)
      Free the given callback trampoline.
      (package private) static byte getByte(long addr) 
      (package private) static byte[] getBytes(String s)
      Return a byte array corresponding to the given String.
      (package private) static byte[] getBytes(String s, String encoding)
      Return a byte array corresponding to the given String, using the given encoding.
      static Callback.UncaughtExceptionHandler getCallbackExceptionHandler()
      Returns the current handler for callback uncaught exceptions.
      (package private) static Class getCallingClass()
      Try to determine the class context in which a register(String) call was made.
      (package private) static char getChar(long addr) 
      static long getComponentID(Component c)
      Utility method to get the native window ID for a heavyweight Java Component as a long value.
      static Pointer getComponentPointer(Component c)
      Utility method to get the native window pointer for a heavyweight Java Component as a Pointer value.
      static String getDefaultStringEncoding()
      Return the default string encoding.
      static Pointer getDirectBufferPointer(Buffer b)
      Convert a direct Buffer into a Pointer.
      static ByteBuffer getDirectByteBuffer(long addr, long length)
      Get a direct ByteBuffer mapped to the memory pointed to by the pointer.
      (package private) static double getDouble(long addr) 
      (package private) static float getFloat(long addr) 
      (package private) static int getInt(long addr) 
      static int getLastError()
      Retrieve last error set by the OS.
      static Map getLibraryOptions(Class type)
      Return the preferred native library configuration options for the given class.
      (package private) static long getLong(long addr) 
      static int getNativeSize(Class cls)
      Returns the native size for a given Java class.
      static int getNativeSize(Class type, Object value)
      Returns the native size of the given class, in bytes.
      (package private) static Pointer getPointer(long addr) 
      static boolean getPreserveLastError()
      Deprecated. 
      Last error is always preserved and available via getLastError()
      (package private) static short getShort(long addr) 
      (package private) static String getString(long addr) 
      (package private) static String getString(long addr, String encoding) 
      (package private) static byte[] getStringBytes(long addr) 
      static String getStringEncoding(Class cls)
      Return the preferred Strring encoding for the given native interface.
      static int getStructureAlignment(Class cls)
      Return the preferred structure alignment for the given native interface.
      (package private) static File getTempDir()
      Obtain a directory suitable for writing JNA-specific temporary files.
      (package private) static Pointer getTerminationFlag(Thread t) 
      static TypeMapper getTypeMapper(Class cls)
      Return the preferred TypeMapper for the given native interface.
      static String getWebStartLibraryPath(String libName)
      If running web start, determine the location of a given native library.
      (package private) static String getWideString(long addr) 
      (package private) static long getWindowHandle0(Component c) 
      static long getWindowID(Window w)
      Utility method to get the native window ID for a Java Window as a long value.
      static Pointer getWindowPointer(Window w)
      Utility method to get the native window pointer for a Java Window as a Pointer value.
      (package private) static long indexOf(long addr, byte value) 
      (package private) static int initialize_ffi_type(long type_info)
      Returns the size (calculated by libffi) of the given type.
      (package private) static double invokeDouble(long fp, int callFlags, Object[] args)
      Call the native function being represented by this object
      (package private) static float invokeFloat(long fp, int callFlags, Object[] args)
      Call the native function being represented by this object
      (package private) static int invokeInt(long fp, int callFlags, Object[] args)
      Call the native function being represented by this object
      (package private) static long invokeLong(long fp, int callFlags, Object[] args)
      Call the native function being represented by this object
      (package private) static Object invokeObject(long fp, int callFlags, Object[] args)
      Call the native function being represented by this object, returning a Java Object.
      (package private) static long invokePointer(long fp, int callFlags, Object[] args)
      Call the native function being represented by this object
      (package private) static Structure invokeStructure(long fp, int callFlags, Object[] args, Structure s)
      Call the native function being represented by this object, returning a struct by value.
      (package private) static void invokeVoid(long fp, int callFlags, Object[] args)
      Call the native function being represented by this object
      static boolean isProtected()
      Returns whether protection is enabled.
      static boolean isSupportedNativeType(Class cls)
      Indicate whether the given class is supported as a native argument type.
      (package private) static boolean isUnpacked(File file)
      Identify temporary files unpacked from classpath jar files.
      static Object loadLibrary(Class interfaceClass)
      Map a library interface to the current process, providing the explicit interface class.
      static Object loadLibrary(Class interfaceClass, Map options)
      Map a library interface to the current process, providing the explicit interface class.
      static Object loadLibrary(String name, Class interfaceClass)
      Map a library interface to the given shared library, providing the explicit interface class.
      static Object loadLibrary(String name, Class interfaceClass, Map options)
      Load a library interface from the given shared library, providing the explicit interface class and a map of options for the library.
      static void main(String[] args)
      Prints JNA library details to the console.
      static long malloc(long size)
      Call the real native malloc
      (package private) static void markTemporaryFile(File file)
      Perform cleanup of automatically unpacked native shared library.
      (package private) static long open(String name)
      Open the requested native library with default options.
      (package private) static long open(String name, int flags)
      Open the requested native library with the specified platform-specific otions.
      static float parseVersion(String v) 
      (package private) static void read(long addr, byte[] buf, int index, int length) 
      (package private) static void read(long addr, char[] buf, int index, int length) 
      (package private) static void read(long addr, double[] buf, int index, int length) 
      (package private) static void read(long addr, float[] buf, int index, int length) 
      (package private) static void read(long addr, int[] buf, int index, int length) 
      (package private) static void read(long addr, long[] buf, int index, int length) 
      (package private) static void read(long addr, short[] buf, int index, int length) 
      static void register(Class cls, NativeLibrary lib)
      When called from a class static initializer, maps all native methods found within that class to native libraries via the JNA raw calling interface.
      static void register(Class cls, String libName)
      When called from a class static initializer, maps all native methods found within that class to native libraries via the JNA raw calling interface.
      static void register(NativeLibrary lib)
      When called from a class static initializer, maps all native methods found within that class to native libraries via the JNA raw calling interface.
      static void register(String libName)
      When called from a class static initializer, maps all native methods found within that class to native libraries via the JNA raw calling interface.
      static boolean registered(Class cls) 
      (package private) static void removeTemporaryFiles()
      Remove all marked temporary files in the given directory.
      (package private) static String replace(String s1, String s2, String str) 
      (package private) static void setByte(long addr, byte value) 
      static void setCallbackExceptionHandler(Callback.UncaughtExceptionHandler eh)
      Set the default handler invoked when a callback throws an uncaught exception.
      static void setCallbackThreadInitializer(Callback cb, CallbackThreadInitializer initializer)
      Set a thread initializer for the given callback.
      (package private) static void setChar(long addr, char value) 
      (package private) static void setDouble(long addr, double value) 
      (package private) static void setFloat(long addr, float value) 
      (package private) static void setInt(long addr, int value) 
      static void setLastError(int code)
      Set the OS last error code.
      (package private) static void setLong(long addr, long value) 
      (package private) static void setMemory(long addr, long length, byte value) 
      (package private) static void setPointer(long addr, long value) 
      static void setPreserveLastError(boolean enable)
      Deprecated. 
      Last error is always preserved and available via getLastError()
      static void setProtected(boolean enable)
      Set whether native memory accesses are protected from invalid accesses.
      (package private) static void setShort(long addr, short value) 
      (package private) static void setWideString(long addr, String value) 
      static Library synchronizedLibrary(Library library)
      Returns a synchronized (thread-safe) library backed by the specified library.
      static byte[] toByteArray(String s)
      Obtain a NUL-terminated byte buffer equivalent to the given String, using the encoding returned by getDefaultStringEncoding().
      static byte[] toByteArray(String s, String encoding)
      Obtain a NUL-terminated byte buffer equivalent to the given String, using the given encoding.
      static char[] toCharArray(String s)
      Obtain a NUL-terminated wide character buffer equivalent to the given String.
      static String toString(byte[] buf)
      Obtain a Java String from the given native byte array.
      static String toString(byte[] buf, String encoding)
      Obtain a Java String from the given native byte array, using the given encoding.
      static String toString(char[] buf)
      Obtain a Java String from the given native wchar_t array.
      static List<String> toStringList(char[] buf)
      Converts a "list" of strings each null terminated into a List of String values.
      static List<String> toStringList(char[] buf, int offset, int len)
      Converts a "list" of strings each null terminated into a List of String values.
      static void unregister()
      Remove all native mappings for the calling class.
      static void unregister(Class cls)
      Remove all native mappings for the given class.
      (package private) static void write(long addr, byte[] buf, int index, int length) 
      (package private) static void write(long addr, char[] buf, int index, int length) 
      (package private) static void write(long addr, double[] buf, int index, int length) 
      (package private) static void write(long addr, float[] buf, int index, int length) 
      (package private) static void write(long addr, int[] buf, int index, int length) 
      (package private) static void write(long addr, long[] buf, int index, int length) 
      (package private) static void write(long addr, short[] buf, int index, int length) 
    • Field Detail

      • DEBUG_LOAD

        static final boolean DEBUG_LOAD
      • DEBUG_JNA_LOAD

        static final boolean DEBUG_JNA_LOAD
      • jnidispatchPath

        static String jnidispatchPath
      • POINTER_SIZE

        public static final int POINTER_SIZE
        The size of a native pointer (void*) on the current platform, in bytes.
      • LONG_SIZE

        public static final int LONG_SIZE
        Size of a native long type, in bytes.
      • WCHAR_SIZE

        public static final int WCHAR_SIZE
        Size of a native wchar_t type, in bytes.
      • SIZE_T_SIZE

        public static final int SIZE_T_SIZE
        Size of a native size_t type, in bytes.
      • MAX_ALIGNMENT

        static final int MAX_ALIGNMENT
      • MAX_PADDING

        static final int MAX_PADDING
      • CB_HAS_INITIALIZER

        static final int CB_HAS_INITIALIZER
        Indicates whether the callback has an initializer.
        See Also:
        Constant Field Values
      • CB_OPTION_DIRECT

        static final int CB_OPTION_DIRECT
        Use direct mapping for callback.
        See Also:
        Constant Field Values
      • CB_OPTION_IN_DLL

        static final int CB_OPTION_IN_DLL
        Return a DLL-resident fucntion pointer.
        See Also:
        Constant Field Values
    • Method Detail

      • parseVersion

        public static float parseVersion(String v)
      • deleteLibrary

        static boolean deleteLibrary(File lib)
        Remove any automatically unpacked native library. This will fail on windows, which disallows removal of any file that is still in use, so an alternative is required in that case. Mark the file that could not be deleted, and attempt to delete any temporaries on next startup. Do NOT force the class loader to unload the native library, since that introduces issues with cleaning up any extant JNA bits (e.g. Memory) which may still need use of the library before shutdown.
      • setProtected

        public static void setProtected(boolean enable)
        Set whether native memory accesses are protected from invalid accesses. This should only be set true when testing or debugging, and should not be considered reliable or robust for applications where JNA native calls are occurring on multiple threads. Protected mode will be automatically set if the system property jna.protected has a value of "true" when the JNA library is first loaded.

        If not supported by the underlying platform, this setting will have no effect.

        NOTE: On platforms which support signals (non-Windows), JNA uses signals to trap errors. This may interfere with the JVM's own use of signals. When protected mode is enabled, you should make use of the jsig library, if available (see Signal Chaining). In short, set the environment variable LD_PRELOAD to the path to libjsig.so in your JRE lib directory (usually ${java.home}/lib/${os.arch}/libjsig.so) before launching your Java application.

      • isProtected

        public static boolean isProtected()
        Returns whether protection is enabled. Check the result of this method after calling setProtected(true) to determine if this platform supports protecting memory accesses.
      • setPreserveLastError

        @Deprecated
        public static void setPreserveLastError(boolean enable)
        Deprecated. Last error is always preserved and available via getLastError()
        This method is obsolete. The last error value is always preserved.
        See Also:
        getLastError()
      • getPreserveLastError

        @Deprecated
        public static boolean getPreserveLastError()
        Deprecated. Last error is always preserved and available via getLastError()
        Indicates whether the system last error result is preserved after every invocation. Always returns true

        See Also:
        getLastError()
      • getWindowID

        public static long getWindowID(Window w)
                                throws HeadlessException
        Utility method to get the native window ID for a Java Window as a long value. This method is primarily for X11-based systems, which use an opaque XID (usually long int) to identify windows.
        Throws:
        HeadlessException - if the current VM is running headless
      • getComponentID

        public static long getComponentID(Component c)
                                   throws HeadlessException
        Utility method to get the native window ID for a heavyweight Java Component as a long value. This method is primarily for X11-based systems, which use an opaque XID (usually long int) to identify windows.
        Throws:
        HeadlessException - if the current VM is running headless
      • getWindowPointer

        public static Pointer getWindowPointer(Window w)
                                        throws HeadlessException
        Utility method to get the native window pointer for a Java Window as a Pointer value. This method is primarily for w32, which uses the HANDLE type (actually void *) to identify windows.
        Throws:
        HeadlessException - if the current VM is running headless
      • getComponentPointer

        public static Pointer getComponentPointer(Component c)
                                           throws HeadlessException
        Utility method to get the native window pointer for a heavyweight Java Component as a Pointer value. This method is primarily for w32, which uses the HWND type (actually void *) to identify windows.
        Throws:
        HeadlessException - if the current VM is running headless
      • getWindowHandle0

        static long getWindowHandle0(Component c)
      • toString

        public static String toString(byte[] buf)
        Obtain a Java String from the given native byte array. If there is no NUL terminator, the String will comprise the entire array. The encoding is obtained from getDefaultStringEncoding().
        Parameters:
        buf - The buffer containing the encoded bytes
        See Also:
        toString(byte[], String)
      • toString

        public static String toString(byte[] buf,
                                      String encoding)
        Obtain a Java String from the given native byte array, using the given encoding. If there is no NUL terminator, the String will comprise the entire array.
        Parameters:
        buf - The buffer containing the encoded bytes
        encoding - The encoding name - if null then the platform default encoding will be used
      • toString

        public static String toString(char[] buf)
        Obtain a Java String from the given native wchar_t array. If there is no NUL terminator, the String will comprise the entire array.
        Parameters:
        buf - The buffer containing the characters
      • toStringList

        public static List<String> toStringList(char[] buf)
        Converts a "list" of strings each null terminated into a List of String values. The end of the list is signaled by an extra NULL value at the end or by the end of the buffer.
        Parameters:
        buf - The buffer containing the strings
        Returns:
        A List of all the strings in the buffer
        See Also:
        toStringList(char[], int, int)
      • toStringList

        public static List<String> toStringList(char[] buf,
                                                int offset,
                                                int len)
        Converts a "list" of strings each null terminated into a List of String values. The end of the list is signaled by an extra NULL value at the end or by the end of the data.
        Parameters:
        buf - The buffer containing the strings
        offset - Offset to start parsing
        len - The total characters to parse
        Returns:
        A List of all the strings in the buffer
      • loadLibrary

        public static Object loadLibrary(Class interfaceClass)
        Map a library interface to the current process, providing the explicit interface class. Native libraries loaded via this method may be found in several locations.
        Parameters:
        interfaceClass -
        Returns:
        an instance of the requested interface, mapped to the current process.
        Throws:
        UnsatisfiedLinkError - if the library cannot be found or dependent libraries are missing.
      • loadLibrary

        public static Object loadLibrary(Class interfaceClass,
                                         Map options)
        Map a library interface to the current process, providing the explicit interface class. Any options provided for the library are cached and associated with the library and any of its defined structures and/or functions. Native libraries loaded via this method may be found in several locations.
        Parameters:
        interfaceClass -
        options - Map of library options
        Returns:
        an instance of the requested interface, mapped to the current process.
        Throws:
        UnsatisfiedLinkError - if the library cannot be found or dependent libraries are missing.
      • loadLibrary

        public static Object loadLibrary(String name,
                                         Class interfaceClass)
        Map a library interface to the given shared library, providing the explicit interface class. If name is null, attempts to map onto the current process. Native libraries loaded via this method may be found in several locations.
        Parameters:
        name -
        interfaceClass -
        Returns:
        an instance of the requested interface, mapped to the indicated native library.
        Throws:
        UnsatisfiedLinkError - if the library cannot be found or dependent libraries are missing.
      • loadLibrary

        public static Object loadLibrary(String name,
                                         Class interfaceClass,
                                         Map options)
        Load a library interface from the given shared library, providing the explicit interface class and a map of options for the library. If no library options are detected the map is interpreted as a map of Java method names to native function names.

        If name is null, attempts to map onto the current process. Native libraries loaded via this method may be found in several locations.

        Parameters:
        name -
        interfaceClass -
        options - Map of library options
        Returns:
        an instance of the requested interface, mapped to the indicated native library.
        Throws:
        UnsatisfiedLinkError - if the library cannot be found or dependent libraries are missing.
      • findEnclosingLibraryClass

        static Class findEnclosingLibraryClass(Class cls)
        Find the library interface corresponding to the given class. Checks all ancestor classes and interfaces for a declaring class which implements Library.
      • getLibraryOptions

        public static Map getLibraryOptions(Class type)
        Return the preferred native library configuration options for the given class. First attempts to load any field of the interface type within the interface mapping, then checks the cache for any specified library options. If none found, a set of library options will be generated from the fields (by order of precedence) OPTIONS (a Map), TYPE_MAPPER (a TypeMapper), STRUCTURE_ALIGNMENT (an Integer), and STRING_ENCODING (a String).
        See Also:
        Library
      • getDefaultStringEncoding

        public static String getDefaultStringEncoding()
        Return the default string encoding. Returns the value of the system property jna.encoding or DEFAULT_ENCODING.
      • getBytes

        static byte[] getBytes(String s)
        Return a byte array corresponding to the given String. The encoding used is obtained from getDefaultStringEncoding().
      • getBytes

        static byte[] getBytes(String s,
                               String encoding)
        Return a byte array corresponding to the given String, using the given encoding. If the encoding is not found default to the platform native encoding.
      • toByteArray

        public static byte[] toByteArray(String s)
        Obtain a NUL-terminated byte buffer equivalent to the given String, using the encoding returned by getDefaultStringEncoding().
      • toByteArray

        public static byte[] toByteArray(String s,
                                         String encoding)
        Obtain a NUL-terminated byte buffer equivalent to the given String, using the given encoding.
      • toCharArray

        public static char[] toCharArray(String s)
        Obtain a NUL-terminated wide character buffer equivalent to the given String.
      • isUnpacked

        static boolean isUnpacked(File file)
        Identify temporary files unpacked from classpath jar files.
      • extractFromResourcePath

        public static File extractFromResourcePath(String name)
                                            throws IOException
        Attempt to extract a native library from the current resource path, using the current thread context class loader.
        Parameters:
        name - Base name of native library to extract. May also be an absolute resource path (i.e. starts with "/"), in which case the no transformations of the library name are performed. If only the base name is given, the resource path is attempted both with and without Platform.RESOURCE_PREFIX, after mapping the library name via NativeLibrary.mapSharedLibraryName(String).
        Returns:
        File indicating extracted resource on disk
        Throws:
        IOException - if resource not found
      • extractFromResourcePath

        public static File extractFromResourcePath(String name,
                                                   ClassLoader loader)
                                            throws IOException
        Attempt to extract a native library from the resource path using the given class loader.
        Parameters:
        name - Base name of native library to extract. May also be an absolute resource path (i.e. starts with "/"), in which case the no transformations of the library name are performed. If only the base name is given, the resource path is attempted both with and without Platform.RESOURCE_PREFIX, after mapping the library name via NativeLibrary.mapSharedLibraryName(String).
        loader - Class loader to use to load resources
        Returns:
        File indicating extracted resource on disk
        Throws:
        IOException - if resource not found
      • getLastError

        public static int getLastError()
        Retrieve last error set by the OS. This corresponds to GetLastError() on Windows, and errno on most other platforms. The value is preserved per-thread, but whether the original value is per-thread depends on the underlying OS.

        An alternative method of obtaining the last error result is to declare your mapped method to throw LastErrorException instead. If a method's signature includes a throw of LastErrorException, the last error will be set to zero before the native call and a LastErrorException will be raised if the last error value is non-zero after the call, regardless of the actual returned value from the native function.

      • setLastError

        public static void setLastError(int code)
        Set the OS last error code. The value will be saved on a per-thread basis.
      • synchronizedLibrary

        public static Library synchronizedLibrary(Library library)
        Returns a synchronized (thread-safe) library backed by the specified library. This wrapping will prevent simultaneous invocations of any functions mapped to a given NativeLibrary. Note that the native library may still be sensitive to being called from different threads.

        Parameters:
        library - the library to be "wrapped" in a synchronized library.
        Returns:
        a synchronized view of the specified library.
      • getWebStartLibraryPath

        public static String getWebStartLibraryPath(String libName)
        If running web start, determine the location of a given native library. This value may be used to properly set jna.library.path so that JNA can load libraries identified by the <nativelib> tag in the JNLP configuration file. Returns null if the Web Start native library cache location can not be determined. Note that the path returned may be different for any given library name.

        Use System.getProperty("javawebstart.version") to detect whether your code is running under Web Start.

        Returns:
        null if unable to query the web start loader.
        Throws:
        UnsatisfiedLinkError - if the library can't be found by the Web Start class loader, which usually means it wasn't included as a <nativelib> resource in the JNLP file.
      • markTemporaryFile

        static void markTemporaryFile(File file)
        Perform cleanup of automatically unpacked native shared library.
      • getTempDir

        static File getTempDir()
                        throws IOException
        Obtain a directory suitable for writing JNA-specific temporary files. Override with jna.tmpdir
        Throws:
        IOException
      • removeTemporaryFiles

        static void removeTemporaryFiles()
                                  throws IOException
        Remove all marked temporary files in the given directory.
        Throws:
        IOException
      • getNativeSize

        public static int getNativeSize(Class type,
                                        Object value)
        Returns the native size of the given class, in bytes. For use with arrays.
      • getNativeSize

        public static int getNativeSize(Class cls)
        Returns the native size for a given Java class. Structures are assumed to be struct pointers unless they implement Structure.ByValue.
      • isSupportedNativeType

        public static boolean isSupportedNativeType(Class cls)
        Indicate whether the given class is supported as a native argument type.
      • setCallbackExceptionHandler

        public static void setCallbackExceptionHandler(Callback.UncaughtExceptionHandler eh)
        Set the default handler invoked when a callback throws an uncaught exception. If the given handler is null, the default handler will be reinstated.
      • getCallbackExceptionHandler

        public static Callback.UncaughtExceptionHandler getCallbackExceptionHandler()
        Returns the current handler for callback uncaught exceptions.
      • register

        public static void register(String libName)
        When called from a class static initializer, maps all native methods found within that class to native libraries via the JNA raw calling interface.
        Parameters:
        libName - library name to which functions should be bound
      • register

        public static void register(NativeLibrary lib)
        When called from a class static initializer, maps all native methods found within that class to native libraries via the JNA raw calling interface.
        Parameters:
        lib - native library to which functions should be bound
      • findDirectMappedClass

        static Class findDirectMappedClass(Class cls)
        Find the nearest enclosing class with native methods.
      • getCallingClass

        static Class getCallingClass()
        Try to determine the class context in which a register(String) call was made.
      • setCallbackThreadInitializer

        public static void setCallbackThreadInitializer(Callback cb,
                                                        CallbackThreadInitializer initializer)
        Set a thread initializer for the given callback. The thread initializer indicates desired thread configuration when the given Callback is invoked on a native thread not yet attached to the VM.
      • unregister

        public static void unregister()
        Remove all native mappings for the calling class. Should only be called if the class is no longer referenced and about to be garbage collected.
      • unregister

        public static void unregister(Class cls)
        Remove all native mappings for the given class. Should only be called if the class is no longer referenced and about to be garbage collected.
      • registered

        public static boolean registered(Class cls)
        Returns:
        whether the given class's native components are registered.
      • register

        public static void register(Class cls,
                                    String libName)
        When called from a class static initializer, maps all native methods found within that class to native libraries via the JNA raw calling interface. Uses the class loader of the given class to search for the native library in the resource path if it is not found in the system library load path or jna.library.path.
        Parameters:
        cls - Class with native methods to register
        libName - name of or path to native library to which functions should be bound
      • register

        public static void register(Class cls,
                                    NativeLibrary lib)
        When called from a class static initializer, maps all native methods found within that class to native libraries via the JNA raw calling interface.
        Parameters:
        cls - Class with native methods to register
        lib - library to which functions should be bound
      • ffi_prep_cif

        public static long ffi_prep_cif(int abi,
                                        int nargs,
                                        long ffi_return_type,
                                        long ffi_types)
        Create a new cif structure.
      • ffi_call

        public static void ffi_call(long cif,
                                    long fptr,
                                    long resp,
                                    long args)
        Make an FFI function call.
      • ffi_free_closure

        public static void ffi_free_closure(long closure)
      • initialize_ffi_type

        static int initialize_ffi_type(long type_info)
        Returns the size (calculated by libffi) of the given type.
      • main

        public static void main(String[] args)
        Prints JNA library details to the console.
      • freeNativeCallback

        static void freeNativeCallback(long ptr)
        Free the given callback trampoline.
      • createNativeCallback

        static long createNativeCallback(Callback callback,
                                         Method method,
                                         Class[] parameterTypes,
                                         Class returnType,
                                         int callingConvention,
                                         int flags,
                                         String encoding)
        Create a native trampoline to delegate execution to the Java callback.
      • invokeInt

        static int invokeInt(long fp,
                             int callFlags,
                             Object[] args)
        Call the native function being represented by this object
        Parameters:
        fp - function pointer
        callFlags - calling convention to be used
        args - Arguments to pass to the native function
        Returns:
        The value returned by the target native function
      • invokeLong

        static long invokeLong(long fp,
                               int callFlags,
                               Object[] args)
        Call the native function being represented by this object
        Parameters:
        fp - function pointer
        callFlags - calling convention to be used
        args - Arguments to pass to the native function
        Returns:
        The value returned by the target native function
      • invokeVoid

        static void invokeVoid(long fp,
                               int callFlags,
                               Object[] args)
        Call the native function being represented by this object
        Parameters:
        fp - function pointer
        callFlags - calling convention to be used
        args - Arguments to pass to the native function
      • invokeFloat

        static float invokeFloat(long fp,
                                 int callFlags,
                                 Object[] args)
        Call the native function being represented by this object
        Parameters:
        fp - function pointer
        callFlags - calling convention to be used
        args - Arguments to pass to the native function
        Returns:
        The value returned by the target native function
      • invokeDouble

        static double invokeDouble(long fp,
                                   int callFlags,
                                   Object[] args)
        Call the native function being represented by this object
        Parameters:
        fp - function pointer
        callFlags - calling convention to be used
        args - Arguments to pass to the native function
        Returns:
        The value returned by the target native function
      • invokePointer

        static long invokePointer(long fp,
                                  int callFlags,
                                  Object[] args)
        Call the native function being represented by this object
        Parameters:
        fp - function pointer
        callFlags - calling convention to be used
        args - Arguments to pass to the native function
        Returns:
        The native pointer returned by the target native function
      • invokeStructure

        static Structure invokeStructure(long fp,
                                         int callFlags,
                                         Object[] args,
                                         Structure s)
        Call the native function being represented by this object, returning a struct by value.
        Parameters:
        fp - function pointer
        callFlags - calling convention to be used
        args - Arguments to pass to the native function
        Returns:
        the passed-in Structure
      • invokeObject

        static Object invokeObject(long fp,
                                   int callFlags,
                                   Object[] args)
        Call the native function being represented by this object, returning a Java Object.
        Parameters:
        fp - function pointer
        callFlags - calling convention to be used
        args - Arguments to pass to the native function
        Returns:
        The returned Java Object
      • open

        static long open(String name)
        Open the requested native library with default options.
      • open

        static long open(String name,
                         int flags)
        Open the requested native library with the specified platform-specific otions.
      • close

        static void close(long handle)
        Close the given native library.
      • findSymbol

        static long findSymbol(long handle,
                               String name)
      • indexOf

        static long indexOf(long addr,
                            byte value)
      • read

        static void read(long addr,
                         byte[] buf,
                         int index,
                         int length)
      • read

        static void read(long addr,
                         short[] buf,
                         int index,
                         int length)
      • read

        static void read(long addr,
                         char[] buf,
                         int index,
                         int length)
      • read

        static void read(long addr,
                         int[] buf,
                         int index,
                         int length)
      • read

        static void read(long addr,
                         long[] buf,
                         int index,
                         int length)
      • read

        static void read(long addr,
                         float[] buf,
                         int index,
                         int length)
      • read

        static void read(long addr,
                         double[] buf,
                         int index,
                         int length)
      • write

        static void write(long addr,
                          byte[] buf,
                          int index,
                          int length)
      • write

        static void write(long addr,
                          short[] buf,
                          int index,
                          int length)
      • write

        static void write(long addr,
                          char[] buf,
                          int index,
                          int length)
      • write

        static void write(long addr,
                          int[] buf,
                          int index,
                          int length)
      • write

        static void write(long addr,
                          long[] buf,
                          int index,
                          int length)
      • write

        static void write(long addr,
                          float[] buf,
                          int index,
                          int length)
      • write

        static void write(long addr,
                          double[] buf,
                          int index,
                          int length)
      • getByte

        static byte getByte(long addr)
      • getChar

        static char getChar(long addr)
      • getShort

        static short getShort(long addr)
      • getInt

        static int getInt(long addr)
      • getLong

        static long getLong(long addr)
      • getFloat

        static float getFloat(long addr)
      • getDouble

        static double getDouble(long addr)
      • getPointer

        static Pointer getPointer(long addr)
      • getWideString

        static String getWideString(long addr)
      • getString

        static String getString(long addr)
      • getString

        static String getString(long addr,
                                String encoding)
      • getStringBytes

        static byte[] getStringBytes(long addr)
      • setMemory

        static void setMemory(long addr,
                              long length,
                              byte value)
      • setByte

        static void setByte(long addr,
                            byte value)
      • setShort

        static void setShort(long addr,
                             short value)
      • setChar

        static void setChar(long addr,
                            char value)
      • setInt

        static void setInt(long addr,
                           int value)
      • setLong

        static void setLong(long addr,
                            long value)
      • setFloat

        static void setFloat(long addr,
                             float value)
      • setDouble

        static void setDouble(long addr,
                              double value)
      • setPointer

        static void setPointer(long addr,
                               long value)
      • setWideString

        static void setWideString(long addr,
                                  String value)
      • malloc

        public static long malloc(long size)
        Call the real native malloc
        Parameters:
        size - size of the memory to be allocated
        Returns:
        native address of the allocated memory block; zero if the allocation failed.
      • free

        public static void free(long ptr)
        Call the real native free
        Parameters:
        ptr - native address to be freed; a value of zero has no effect, passing an already-freed pointer will cause pain.
      • getDirectByteBuffer

        public static ByteBuffer getDirectByteBuffer(long addr,
                                                     long length)
        Get a direct ByteBuffer mapped to the memory pointed to by the pointer. This method calls through to the JNA NewDirectByteBuffer method.
        Parameters:
        addr - base address of the JNA-originated memory
        length - Length of ByteBuffer
        Returns:
        a direct ByteBuffer that accesses the memory being pointed to,
      • detach

        public static void detach(boolean detach)

        Indicate whether the JVM should detach the current native thread when the current Java code finishes execution. Generally this is used to avoid detaching native threads when it is known that a given thread will be relatively long-lived and call back to Java code frequently.

        This call is lightweight; it only results in an additional JNI crossing if the desired state changes from its last setting.
        Throws:
        IllegalStateException - if detach(true) is called on a thread created by the JVM.
      • getTerminationFlag

        static Pointer getTerminationFlag(Thread t)
JNA API 4.2.0

Copyright © 2007-2015 Timothy Wall. All Rights Reserved.