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package org.graalvm.nativeimage.c.struct;

import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.graalvm.nativeimage.c.CContext;
import org.graalvm.word.PointerBase;

Denotes Java interface that imports a C struct. The interface must extend PointerBase, i.e., it is a word type. There is never a Java class that implements the interface. 
 Field accesses are done via interface methods that are annotated with CField, CFieldAddress, or CFieldOffset. All calls of the interface methods are replaced with the appropriate memory or address arithmetic operations. Here is an example to define a complex number structure: {@codesnippet org.graalvm.nativeimage.StackValueSnippets.ComplexValue} The annotated interface, or an outer class that contains the interface, must be annotated with CContext. Allocate an instances of the struct either by StackValue.get(Class<PointerBase>) or by UnmanagedMemory.malloc(UnsignedWord). To access an array of structs one can define a special addressOf method: 

{@codesnippet org.graalvm.nativeimage.StackValueSnippets.IntOrDouble}
Implementation of such method then allows one to do array arithmetics - e.g. obtain
pointer to the first element of the array and then access the others:

{@codesnippet org.graalvm.nativeimage.StackValueSnippets.acceptIntIntDouble}
See Also:
StackValue
UnmanagedMemory
Since:
19.0/**
 * Denotes Java interface that imports a C struct. The interface must extend {@link PointerBase},
 * i.e., it is a word type. There is never a Java class that implements the interface.
 * <p>
 * Field accesses are done via interface methods that are annotated with {@link CField},
 * {@link CFieldAddress}, or {@link CFieldOffset}. All calls of the interface methods are replaced
 * with the appropriate memory or address arithmetic operations. Here is an example to define a
 * complex number structure:
 *
 * {@codesnippet org.graalvm.nativeimage.StackValueSnippets.ComplexValue}
 *
 * The annotated interface, or an outer class that contains the interface, must be annotated with
 * {@link CContext}. Allocate an instances of the {@code struct} either by
 * {@link org.graalvm.nativeimage.StackValue#get(java.lang.Class)} or by
 * {@link org.graalvm.nativeimage.UnmanagedMemory#malloc(org.graalvm.word.UnsignedWord)}.
 *
 * To access an array of structs one can define a special {@code addressOf} method:
 * <p>
 *
 * {@codesnippet org.graalvm.nativeimage.StackValueSnippets.IntOrDouble}
 *
 * Implementation of such method then allows one to do <em>array arithmetics</em> - e.g. obtain
 * pointer to the first element of the array and then access the others:
 * <p>
 *
 * {@codesnippet org.graalvm.nativeimage.StackValueSnippets.acceptIntIntDouble}
 *
 * @since 19.0
 * @see org.graalvm.nativeimage.StackValue
 * @see org.graalvm.nativeimage.UnmanagedMemory
 */
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.TYPE})
public @interface CStruct {

    
Specifies the name of the imported C struct type. If no name is provided, the type name is
used as the struct name.
Since:
19.0/**
     * Specifies the name of the imported C struct type. If no name is provided, the type name is
     * used as the struct name.
     *
     * @since 19.0
     */
    String value() default "";

    
If marked as incomplete, we will not try to determine the size of the struct.
Since:
19.0/**
     * If marked as incomplete, we will not try to determine the size of the struct.
     *
     * @since 19.0
     */
    boolean isIncomplete() default false;

    
Add the C "struct" keyword to the name specified in value(). 
Since:
19.0/**
     * Add the C "struct" keyword to the name specified in {@link #value()}.
     *
     * @since 19.0
     */
    boolean addStructKeyword() default false;
}