从JNI(Java Native Interface)访问C常量(标题)

我有一个带有头文件c_header.h的C库：

// I'll try to get these values in java
#define PBYTES 64
#define SBYTES 128
#define SGBYTES 128

然后我有这个java代码libbind_jni.java：

package libbind;

public class libbind_jni {
static{
    try {
        System.load("libbind_jni.so");
    } catch (UnsatisfiedLinkError e) {
        System.err.println("Native code library failed to load.n" + e);
        System.exit(1);
    }
}

public static native String[] pubm(String seed);

然后在libbind_jni.java上运行javah我生成JNI头文件jni_header.h：

#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     libbind_libbind_jni
 * Method:    pubm
 * Signature: (Ljava/lang/String;)[Ljava/lang/String;
 */
JNIEXPORT jobjectArray JNICALL Java_lib_f_1jni_pubm
  (JNIEnv *,jclass,jstring);

然后我为JNI库jni_source.c写了一个小C代码：

#include "jni_header.h"
#include "c_header.h"
#include <stdlib.h>

JNIEXPORT jobjectArray JNICALL Java_libbind_libbind_1jni_pubm
  (JNIEnv *env,jclass cls,jstring jniSeed){
    unsigned char vk[PBYTES];
    unsigned char sk[SBYTES];
    <whatever...>
}

– 这里编译java库的库 – libbind.so

而JAVA源码j_source.java：

import libbind.libbind_jni;

public class test {

    /* trying to access constants from library (libbind.so) */
    System.out.println(libbind_jni.PBYTES);
    System.out.println(libbind_jni.SBYTES);
    System.out.println(libbind_jni.SGBYTES);

}
public static void main(String[] args) {
    test();
}


$javac test.java

test.java:5: cannot find symbol
symbol  : variable PBYTES
location: class libbind.libbind_jni
    System.out.println(libbind_jni.PBYTES);

所以问题是：如何从Java访问C头文件中的这些定义/常量？

谢谢.