Question

我在jna中遇到一个非常简单的例子。我想用C语言在C语言中读取和写入结构。我在c：

中编译了一个非常简单的例子

typedef struct {
    int x;
} MyStruct;

我使用JNA在java中创建了相应的类：

import java.util.List;
import com.sun.jna.Pointer;
import com.sun.jna.Structure;

public class MyStruct extends Structure {
    public int x;

    public MyStruct(Pointer p) {
        super(p);
    }

    @Override
    protected List<String> getFieldOrder() {
        return List.of("x");
    }
}

我创建了一个测试结构的程序：

public class JnaJava {
    public static void main(String[] args) {
        NativeLibrary lib = NativeLibrary.getInstance(new File("libJnaC.so").getAbsolutePath());
        MyStruct struct = new MyStruct(lib.getGlobalVariableAddress("myStruct"));
        for (int i = 0; i < 2000000000; i++) {
            struct.writeField("x", i);
            System.out.println("val: " + struct.readField("x") + " it: " + i);
        }
    }
}

但我在400.000次迭代中遇到错误：

...

val：448536 it：448536

# A fatal error has been detected by the Java Runtime Environment:
# SIGSEGV (0xb) at pc=0x00007fb3d89e537b, pid=14464, tid=14466
# JRE version: Java(TM) SE Runtime Environment (10.0+46) (build 10+46)
# Java VM: Java HotSpot(TM) 64-Bit Server VM (10+46, mixed mode, tiered, compressed oops, g1 gc, linux-amd64)
# Problematic frame:
# C  [jna8855397332554224295.tmp+0x837b] Java_com_sun_jna_Native_setInt+0xab
# No core dump will be written. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
# An error report file with more information is saved as:
# /home/X/workspace/JnaJava/hs_err_pid14464.log
# If you would like to submit a bug report, please visit:
#   http://bugreport.java.com/bugreport/crash.jsp
# The crash happened outside the Java Virtual Machine in native code.
# See problematic frame for where to report the bug.

有人能告诉我我的错误在哪里吗？这听起来像一个奇怪的记忆错误，但我不知道为什么？

提前致谢

马克

Answer 1

这只是一个愚蠢的GC问题。将变量放入强引用中解决了问题。

https://groups.google.com/forum/#!topic/jna-users/4g3fLVi8Gxw

JNA结构导致致命错误

1 个答案: