如何使用外部函数从Java中获取C++ struct 的返回值&；内存API

当我try 在C++中获取 struct 返回值时，我无法解析 struct 中的值.

这就是我的 struct .

struct Point {
    int x;
    int y;
};

这是我的C++方法

Point test_point(Point points[],long count)
{
    if (count <= 0) {
        // Return a default Point with x and y set to 0
        Point defaultPoint = { 0, 0 };
        return defaultPoint;
    }

    Point maxPoint = points[0];
    int maxSum = maxPoint.x + maxPoint.y;

    for (int i = 1; i < count; ++i) {
        int currentSum = points[i].x + points[i].y;
        if (currentSum > maxSum) {
            maxSum = currentSum;
            maxPoint = points[i];
        }
    }

    int x = maxPoint.x;
    int y = maxPoint.y;
    std::cout << "x = " << x << ", y = " << y << std::endl;
    return maxPoint;
}

这是我的Java方法

public static void dereferenceSegmentsStruct() throws Throwable {
    Linker linker = Linker.nativeLinker();
    SymbolLookup symbolLookup = SymbolLookup.loaderLookup();
    MethodHandle test_point = linker.downcallHandle(
            symbolLookup.find("test_point").orElseThrow(),
            FunctionDescriptor.of(ADDRESS, ADDRESS, JAVA_LONG)
    );

    StructLayout structLayout = MemoryLayout.structLayout(
            JAVA_INT.withName("x"),
            JAVA_INT.withName("y"));

    SequenceLayout ptsLayout = MemoryLayout.sequenceLayout(10, structLayout);

    VarHandle xHandle    // (MemorySegment, long) -> int
            = ptsLayout.varHandle(PathElement.sequenceElement(),
            PathElement.groupElement("x"));
    VarHandle yHandle    // (MemorySegment, long) -> int
            = ptsLayout.varHandle(PathElement.sequenceElement(),
            PathElement.groupElement("y"));

    MemorySegment segment = Arena.ofAuto().allocate(ptsLayout);
    for (int i = 0; i < ptsLayout.elementCount(); i++) {
        xHandle.set(segment,
                /* index */ (long) i,
                /* value to write */ i); // x
        yHandle.set(segment,
                /* index */ (long) i,
                /* value to write */ i); // y
    }

    MemorySegment result = (MemorySegment) test_point.invoke(segment, ptsLayout.elementCount());
    result = result.reinterpret(structLayout.byteSize());
    System.out.println(result.getAtIndex(JAVA_INT, 0));
}

我看到零长度，我试着用一种方法来修改零长度.

image个

我仍然不能得到它，它给出以下错误.

Exception in thread "main" java.lang.IllegalArgumentException: Misaligned access at address: 38654705673
    at java.base/java.lang.invoke.VarHandleSegmentViewBase.newIllegalArgumentExceptionForMisalignedAccess(VarHandleSegmentViewBase.java:57)
    at java.base/java.lang.invoke.VarHandleSegmentAsInts.offsetNoVMAlignCheck(VarHandleSegmentAsInts.java:100)
    at java.base/java.lang.invoke.VarHandleSegmentAsInts.get(VarHandleSegmentAsInts.java:111)
    at java.base/java.lang.foreign.MemorySegment.getAtIndex(MemorySegment.java:1921)
    at org.example/org.example.TestNative.dereferenceSegmentsStruct(TestNative.java:109)
    at org.example/org.example.TestNative.main(TestNative.java:33)

我需要做什么来读取在C++中返回的Point的x和y？