JNA中的未知源错误（在C中返回结构数组函数）

Question

typedef struct A{
    double Value;
    char Type; 
    char Name[100];
    char SymbolTableName[100];
    int updateMode;
    int dataType;
    char ulSize;
} A;

typedef struct B{
    int numAs;
    struct A* as;
} B;

B fill(void){   
    B sVal;
    sVal.numAs=100;
    int i=0;
    sVal.as = (A*)malloc(sizeof(A) * sVal.numAs);
    memset(sVal.as, 0, sizeof(A) * sVal.numAs);
    //X in scope , everything is ok here.
    X= ReadShared(); // It return struct array , X is struct same type.
    for(i=0; i<sVal.numAs; i++)
    {
        sVal.as[i].Value=X->datas[i].Value; 
        sVal.as[i].Type=X->datas[i].Type;
        strcpy(sVal.as[i].Name,X->datas[i].Name);
        strcpy(sVal.as[i].SymbolTableName,X->datas[i].SymbolTableName);
        sVal.as[i].updateMode=X->datas[i].updateMode;   
        sVal.as[i].dataType=X->datas[i].dataType;   
        sVal.as[i].ulSize=X->datas[i].ulSize;           
    }
    return sVal;

}

public class TestClass {

    public interface Test extends Library {

        public static class A extends Structure {
            public static class ByReference extends A implements Structure.ByReference{}
            double Value;
            char Type; 
            char Name;
            char SymbolTableName;
            int updateMode;
            int dataType;
            char ulSize;

            protected List getFieldOrder() {
                // TODO Auto-generated method stub
                return null;
            }
        }

        public static class B extends Structure {
            public static class ByValue extends B implements Structure.ByValue {}

            public int numAs;
            public A.ByReference as;
            protected List getFieldOrder() {
                // TODO Auto-generated method stub
                return null;
            }
        }

        public B.ByValue fill();
    }

    /**
     * @param args
     */
    public   TestClass(){

    }
    static void funcc(){
        NativeLibrary.addSearchPath("tester", "/root/Desktop/");//Path is true
        Test test=(Test)Native.loadLibrary("tester", Test.class);
        Test.B.ByValue jig=test.fill();

        Test.A[] Avals = (Test.A[])jig.as.toArray(jig.numAs);
    }
}

Answer 1

您还没有在structure类中定义结构字段的顺序。JNA需要这些信息才能正确地从本机内存读写。

您还错误地映射了本机char和char[]。

对于类A，需要以下内容：

double Value;
byte Type; 
byte[] Name = new byte[100];
byte[] SymbolTableName = new byte[100];
int updateMode;
int dataType;
byte ulSize;

protected List getFieldOrder() {
    return Arrays.asList("Value", "Type", "Name", "SymbolTableName", "updateMode", "dataType", "ulSize");
}

protected List getFieldOrder() {
    return Arrays.asList("numAs", "as");
}