org.graalvm.nativeimage.c.function

Annotation Type CFunction

@Retention(value=RUNTIME)
 @Target(value=METHOD)
public @interface CFunction

Denotes a native method that calls directly from Java to C, without following the JNI protocol. This means that there are no artificial additional parameters such as the JNI environment passed, and no marshaling or processing of arguments (such as creating handles for objects) is performed. If the method is non-static, the receiver will be ignored.

Parameter types and return types must not be Java reference types, only primitive Java types, word types and CEnum types are allowed. The representation of passed primitive values matches exactly how they are specified in the Java language, for example, int as a 32-bit signed integer or char as a 16-bit unsigned integer. boolean is specified as a single byte that corresponds to true if non-zero, and to false if zero. If a Word value is passed that points to a Java object, no guarantees are taken regarding its integrity as a pointer.

The class containing the annotated method must be annotated with CContext.

Since:

19.0

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element and Description
CFunction.Transition	transition The Java-to-C thread transition code used when calling the function.
String	value The symbol name to use to link this method.

Element Detail

value

public abstract String value

The symbol name to use to link this method. If no value is specified, the name of the method (without name mangling or a class name prefix) is used.

Since:

19.0

Default:

""

transition

public abstract CFunction.Transition transition

The Java-to-C thread transition code used when calling the function.

Since:

19.0

Default:

org.graalvm.nativeimage.c.function.CFunction.Transition.TO_NATIVE