Function (JNA API)

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JNA API 4.0.0

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com.sun.jna
Class Function

java.lang.Object
  com.sun.jna.Pointer
      com.sun.jna.Function

public class Function
extends Pointer
extends Pointer

An abstraction for a native function pointer. An instance of Function represents a pointer to some native function. invoke(Class,Object[],Map) is the primary means to call the function.

Function call behavior may be modified by passing one of the following call flags:

C_CONVENTION Use C calling convention (default)
ALT_CONVENTION Use alternate calling convention (e.g. stdcall)
THROW_LAST_ERROR Throw a LastErrorException if the native function sets the system error to a non-zero value (errno or GetLastError). Setting this flag will cause the system error to be cleared prior to native function invocation.

Author:: Sheng Liang, originator, Todd Fast, suitability modifications, Timothy Wall
See Also:: Pointer

Nested Class Summary
`static interface`	`Function.PostCallRead` Any argument which implements this interface will have the `Function.PostCallRead.read()` method called immediately after function invocation.

Field Summary
`static int`	`ALT_CONVENTION` First alternate convention (currently used only for w32 stdcall).
`static int`	`C_CONVENTION` Standard C calling convention.
`(package private) int`	`callFlags`
`(package private) String`	`encoding`
`(package private) static Integer`	`INTEGER_FALSE`
`(package private) static Integer`	`INTEGER_TRUE`
`static int`	`MAX_NARGS` Maximum number of arguments supported by a JNA function call.
`(package private) static String`	`OPTION_INVOKING_METHOD` For internal JNA use.
`(package private) Map`	`options`
`static int`	`THROW_LAST_ERROR` Whether to throw an exception if last error is non-zero after call.

Fields inherited from class com.sun.jna.Pointer
`NULL, peer, SIZE`

Constructor Summary
`Function(NativeLibrary library, String functionName, int callFlags, String encoding)` Create a new `Function` that is linked with a native function that follows the given calling convention.
`Function(Pointer functionAddress, int callFlags, String encoding)` Create a new `Function` that is linked with a native function that follows the given calling convention.

Method Summary
`(package private) static Object[]`	`concatenateVarArgs(Object[] inArgs)` Concatenate varargs with normal args to obtain a simple argument array.
`boolean`	`equals(Object o)` Two function pointers are equal if they share the same peer address and calling convention.
`int`	`getCallingConvention()`
`static Function`	`getFunction(Pointer p)` Obtain a `Function` representing a native function pointer.
`static Function`	`getFunction(Pointer p, int callFlags)` Obtain a `Function` representing a native function pointer.
`static Function`	`getFunction(String libraryName, String functionName)` Obtain a `Function` representing a native function that follows the standard "C" calling convention.
`static Function`	`getFunction(String libraryName, String functionName, int callFlags)` Obtain a `Function` representing a native function.
`static Function`	`getFunction(String libraryName, String functionName, int callFlags, String encoding)` Obtain a `Function` representing a native function.
`String`	`getName()`
`int`	`hashCode()` Provide a unique hash code for `Function`s which are equivalent.
`Object`	`invoke(Class returnType, Object[] inArgs)` Invoke the native function with the given arguments, returning the native result as an Object.
`Object`	`invoke(Class returnType, Object[] inArgs, Map options)` Invoke the native function with the given arguments, returning the native result as an Object.
`void`	`invoke(Object[] args)` Call the native function being represented by this object
`(package private) Object`	`invoke(Object[] args, Class returnType, boolean allowObjects)`
`double`	`invokeDouble(Object[] args)` Convenience method for `invoke(Double.class, args)`.
`float`	`invokeFloat(Object[] args)` Convenience method for `invoke(Float.class, args)`.
`int`	`invokeInt(Object[] args)` Convenience method for `invoke(Integer.class, args)`.
`long`	`invokeLong(Object[] args)` Convenience method for `invoke(Long.class, args)`.
`Object`	`invokeObject(Object[] args)` Convenience method for `invokeObject(Object.class, args)`.
`Pointer`	`invokePointer(Object[] args)` Convenience method for `invoke(Pointer.class, args)`.
`String`	`invokeString(Object[] args, boolean wide)` Convenience method for `invoke(String.class, args)` or `invoke(WString.class, args)`
`void`	`invokeVoid(Object[] args)` Convenience method for `invoke(Void.class, args)`.
`(package private) static boolean`	`isVarArgs(Method m)` Varargs are only supported on 1.5+.
`String`	`toString()` Provide a human-readable representation of this object.
`(package private) static Boolean`	`valueOf(boolean b)` Implementation of Boolean.valueOf for older VMs.

Methods inherited from class com.sun.jna.Pointer
clear, createConstant, createConstant, dump, getByte, getByteArray, getByteBuffer, getChar, getCharArray, getDouble, getDoubleArray, getFloat, getFloatArray, getInt, getIntArray, getLong, getLongArray, getNativeLong, getPointer, getPointerArray, getPointerArray, getShort, getShortArray, getString, getString, getString, getStringArray, getStringArray, getStringArray, getStringArray, getStringArray, getStringArray, getValue, getWideString, getWideStringArray, getWideStringArray, indexOf, nativeValue, nativeValue, read, read, read, read, read, read, read, read, setByte, setChar, setDouble, setFloat, setInt, setLong, setMemory, setNativeLong, setPointer, setShort, setString, setString, setString, setString, setValue, setWideString, share, share, write, write, write, write, write, write, write, write

Methods inherited from class com.sun.jna.Pointer

clear, createConstant, createConstant, dump, getByte, getByteArray, getByteBuffer, getChar, getCharArray, getDouble, getDoubleArray, getFloat, getFloatArray, getInt, getIntArray, getLong, getLongArray, getNativeLong, getPointer, getPointerArray, getPointerArray, getShort, getShortArray, getString, getString, getString, getStringArray, getStringArray, getStringArray, getStringArray, getStringArray, getStringArray, getValue, getWideString, getWideStringArray, getWideStringArray, indexOf, nativeValue, nativeValue, read, read, read, read, read, read, read, read, setByte, setChar, setDouble, setFloat, setInt, setLong, setMemory, setNativeLong, setPointer, setShort, setString, setString, setString, setString, setValue, setWideString, share, share, write, write, write, write, write, write, write, write

Methods inherited from class java.lang.Object
`clone, finalize, getClass, notify, notifyAll, wait, wait, wait`

Field Detail

MAX_NARGS

public static final int MAX_NARGS

Maximum number of arguments supported by a JNA function call.

See Also:: Constant Field Values

C_CONVENTION

public static final int C_CONVENTION

Standard C calling convention.

See Also:: Constant Field Values

ALT_CONVENTION

public static final int ALT_CONVENTION

First alternate convention (currently used only for w32 stdcall).

See Also:: Constant Field Values

THROW_LAST_ERROR

public static final int THROW_LAST_ERROR

Whether to throw an exception if last error is non-zero after call.

See Also:: Constant Field Values

INTEGER_TRUE

static final Integer INTEGER_TRUE

INTEGER_FALSE

static final Integer INTEGER_FALSE

encoding

final String encoding

callFlags

final int callFlags

options

final Map options

OPTION_INVOKING_METHOD

static final String OPTION_INVOKING_METHOD

For internal JNA use.

See Also:: Constant Field Values

Constructor Detail

Function

Function(NativeLibrary library,
         String functionName,
         int callFlags,
         String encoding)

Create a new Function that is linked with a native function that follows the given calling convention.

The allocated instance represents a pointer to the named native function from the supplied library, called with the given calling convention.

Parameters:: library - NativeLibrary in which to find the function; functionName - Name of the native function to be linked with; callFlags - Function call flags; encoding - Encoding for conversion between Java and native strings.
Throws:: {@link - UnsatisfiedLinkError} if the given function name is not found within the library.

Function

Function(Pointer functionAddress,
         int callFlags,
         String encoding)

Create a new Function that is linked with a native function that follows the given calling convention.

The allocated instance represents a pointer to the given function address, called with the given calling convention.

Parameters:: functionAddress - Address of the native function; callFlags - Function call flags; encoding - Encoding for conversion between Java and native strings.

Method Detail

getFunction

public static Function getFunction(String libraryName,
                                   String functionName)

Obtain a Function representing a native function that follows the standard "C" calling convention.

The allocated instance represents a pointer to the named native function from the named library, called with the standard "C" calling convention.

Parameters:: libraryName - Library in which to find the native function; functionName - Name of the native function to be linked with
Throws:: {@link - UnsatisfiedLinkError} if the library is not found or the given function name is not found within the library.

getFunction

public static Function getFunction(String libraryName,
                                   String functionName,
                                   int callFlags)

Obtain a Function representing a native function.

The allocated instance represents a pointer to the named native function from the named library.

Parameters:: libraryName - Library in which to find the function; functionName - Name of the native function to be linked with; callFlags - Function call flags
Throws:: {@link - UnsatisfiedLinkError} if the library is not found or the given function name is not found within the library.

getFunction

public static Function getFunction(String libraryName,
                                   String functionName,
                                   int callFlags,
                                   String encoding)

Obtain a Function representing a native function.

The allocated instance represents a pointer to the named native function from the named library.

Parameters:: libraryName - Library in which to find the function; functionName - Name of the native function to be linked with; callFlags - Function call flags; encoding - Encoding to use for conversion between Java and native strings.
Throws:: {@link - UnsatisfiedLinkError} if the library is not found or the given function name is not found within the library.

getFunction

public static Function getFunction(Pointer p)

Obtain a Function representing a native function pointer. In general, this function should be used by dynamic languages; Java code should allow JNA to bind to a specific Callback interface instead by defining a return type or Structure field type.

The allocated instance represents a pointer to the native function pointer.

Parameters:: p - Native function pointer

getFunction

public static Function getFunction(Pointer p,
                                   int callFlags)

The allocated instance represents a pointer to the native function pointer.

Parameters:: p - Native function pointer; callFlags - Function call flags

getName

public String getName()

getCallingConvention

public int getCallingConvention()

invoke

public Object invoke(Class returnType,
                     Object[] inArgs)

Invoke the native function with the given arguments, returning the native result as an Object.

invoke

public Object invoke(Class returnType,
                     Object[] inArgs,
                     Map options)

Invoke the native function with the given arguments, returning the native result as an Object.

invoke

Object invoke(Object[] args,
              Class returnType,
              boolean allowObjects)

See Also:: implementation

invoke

public void invoke(Object[] args)

Call the native function being represented by this object

Parameters:: args - Arguments to pass to the native function

toString

public String toString()

Provide a human-readable representation of this object.

Overrides:: toString in class Pointer

invokeObject

public Object invokeObject(Object[] args)

Convenience method for invokeObject(Object.class, args).

invokePointer

public Pointer invokePointer(Object[] args)

Convenience method for invoke(Pointer.class, args).

invokeString

public String invokeString(Object[] args,
                           boolean wide)

Convenience method for invoke(String.class, args) or invoke(WString.class, args)

Parameters:: args - Arguments passed to native function; wide - Whether the return value is of type wchar_t*; if false, the return value is of type char*.

invokeInt

public int invokeInt(Object[] args)

Convenience method for invoke(Integer.class, args).

invokeLong

public long invokeLong(Object[] args)

Convenience method for invoke(Long.class, args).

invokeFloat

public float invokeFloat(Object[] args)

Convenience method for invoke(Float.class, args).

invokeDouble

public double invokeDouble(Object[] args)

Convenience method for invoke(Double.class, args).

invokeVoid

public void invokeVoid(Object[] args)

Convenience method for invoke(Void.class, args).

equals

public boolean equals(Object o)

Two function pointers are equal if they share the same peer address and calling convention.

Overrides:: equals in class Pointer

Parameters:: o - A Pointer instance
Returns:: True if the other object is a Pointer, and the C pointers being pointed to by these objects are also equal. Returns false otherwise.

hashCode

public int hashCode()

Provide a unique hash code for Functions which are equivalent.

Overrides:: hashCode in class Pointer

Returns:: A hash code value for the represented native pointer

concatenateVarArgs

static Object[] concatenateVarArgs(Object[] inArgs)

Concatenate varargs with normal args to obtain a simple argument array.

isVarArgs

static boolean isVarArgs(Method m)

Varargs are only supported on 1.5+.

valueOf

static Boolean valueOf(boolean b)

Implementation of Boolean.valueOf for older VMs.

Overview

Package

Class

Tree

Deprecated

Index

Help

JNA API 4.0.0

PREV CLASS NEXT CLASS

FRAMES NO FRAMES

SUMMARY: NESTED | FIELD | CONSTR | METHOD

DETAIL: FIELD | CONSTR | METHOD

com.sun.jna Class Function

MAX_NARGS

C_CONVENTION

ALT_CONVENTION

THROW_LAST_ERROR

INTEGER_TRUE

INTEGER_FALSE

encoding

callFlags

options

OPTION_INVOKING_METHOD

Function

Function

getFunction

getFunction

getFunction

getFunction

getFunction

getName

getCallingConvention

invoke

invoke

invoke

invoke

toString

invokeObject

invokePointer

invokeString

invokeInt

invokeLong

invokeFloat

invokeDouble

invokeVoid

equals

hashCode

concatenateVarArgs

isVarArgs

valueOf

com.sun.jna
Class Function