ldd输出在共享库上静态链接 [英] ldd outputs statically linked on a shared library

问题描述

我正在尝试创建共享库libddv3djava.so

I am trying to create a shared library libddv3djava.so

我像这样编译libddv3djava.so的源代码:

I compile sources for libddv3djava.so like so:

~/Programming/intellijprojects/ddv3dbindingstest/src $ g++ -c -Wall -Werror -I. -I /usr/lib/jvm/java-8-oracle/include/ -I /usr/lib/jvm/java-8-oracle/include/linux/ -fpic com_ddv3d_Ddv3dBinding.cpp

创建libddv3djava.so:

Creating libddv3djava.so:

~/Programming/intellijprojects/ddv3dbindingstest/src $ g++ -shared -o libddv3djava.so com_ddv3d_Ddv3dBinding.o

当我在libddv3djava.so上执行ldd时:

When I do ldd on libddv3djava.so:

~/Programming/intellijprojects/ddv3dbindingstest/src $ ldd libddv3djava.so         statically linked

问题:

它说libddv3djava.so是静态链接的.我使用 -shared 创建了libddv3djava.so，这让我感到困惑.

Problem:

It say's libddv3djava.so is statically linked. I created libddv3djava.so with -shared so this makes me confused.

当libddv3djava.so不是静态链接时，为什么 ldd 输出静态链接?

Why does ldd output statically linked, when libddv3djava.so isn't statically linked?

我不确定以下内容是否相关，但可能如此； libddv3djava.so依赖于我创建的另一个共享库libddv3d.so.基本上libddv3djava.so是围绕libddv3d.so的JNI包装器.发布来源:

I'm not sure if the following is of any relevance, but it could be; libddv3djava.so is dependent on another shared library I created called libddv3d.so. Basically libddv3djava.so is a JNI-wrapper around libddv3d.so. Posting sources:

com_ddv3d_Ddv3dBinding.h:

com_ddv3d_Ddv3dBinding.h:

/* DO NOT EDIT THIS FILE - it is machine generated */
#include <jni.h>
/* Header for class com_ddv3d_Ddv3dBinding */

#ifndef _Included_com_ddv3d_Ddv3dBinding
#define _Included_com_ddv3d_Ddv3dBinding
#ifdef __cplusplus
extern "C" {
#endif
/*
 * Class:     com_ddv3d_Ddv3dBinding
 * Method:    initialize
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_com_ddv3d_Ddv3dBinding_initialize
  (JNIEnv *, jobject);

/*
 * Class:     com_ddv3d_Ddv3dBinding
 * Method:    sendDrawableData
 * Signature: (FFFFFFFI)V
 */
JNIEXPORT void JNICALL Java_com_ddv3d_Ddv3dBinding_sendDrawableData
  (JNIEnv *, jobject, jfloat, jfloat, jfloat, jfloat, jfloat, jfloat, jfloat, jint);

/*
 * Class:     com_ddv3d_Ddv3dBinding
 * Method:    finished
 * Signature: ()Z
 */
JNIEXPORT jboolean JNICALL Java_com_ddv3d_Ddv3dBinding_finished
  (JNIEnv *, jobject);

/*
 * Class:     com_ddv3d_Ddv3dBinding
 * Method:    cleanup
 * Signature: ()V
 */
JNIEXPORT void JNICALL Java_com_ddv3d_Ddv3dBinding_cleanup
  (JNIEnv *, jobject);

#ifdef __cplusplus
}
#endif
#endif

com_ddv3d_Ddv3dBinding.cpp:

com_ddv3d_Ddv3dBinding.cpp:

#include <jni.h>
#include <ddv3d.h>
#include "com_ddv3d_Ddv3dBinding.h"

JNIEXPORT void JNICALL Java_com_ddv3d_Ddv3dBinding_initialize(JNIEnv *env, jobject thisObj)
{
    ddv3d::initialize();
    return;
}
JNIEXPORT void JNICALL Java_com_ddv3d_Ddv3dBinding_sendDrawableData(JNIEnv *env, jobject thisObj,
                jfloat positionX, jfloat positionY, jfloat positionZ,
                jfloat angle,
                jfloat rotationAxisX, jfloat rotationAxisY, jfloat rotationAxisZ,
                jint type)
{
    ddv3d::sendDrawableData(positionX, positionY, positionZ,
                angle,
                rotationAxisX, rotationAxisY, rotationAxisZ,
                type);
    return;
}
JNIEXPORT jboolean JNICALL Java_com_ddv3d_Ddv3dBinding_finished(JNIEnv *env, jobject thisObj)
{
    return ddv3d::finished();
}
JNIEXPORT void JNICALL Java_com_ddv3d_Ddv3dBinding_cleanup(JNIEnv *env, jobject thisObj)
{
    ddv3d::cleanup();
    return;
}

推荐答案

ldd显示库或可执行文件需要哪些共享库. 在这种情况下，没有，因为libddv3djava.so是静态链接的.

ldd shows which shared libraries a library or executable needs. In this case none, because libddv3djava.so is statically linked.

编译器标志-fpic和链接器标志-shared使libddv3djava.so可以用作共享对象.

The compiler flag -fpic and linker flag -shared enables libddv3djava.so to be used as a shared object which is something else.

要使libddv3djava.so依赖共享库文件libddv3d.so，必须将其添加到链接器命令上.

To make libddv3djava.so depend on the shared library file libddv3d.so it must be added on to the linker command.

g ++ -shared -o libddv3djava.so -lddvd3d com_ddv3d_Ddv3dBinding.o

g++ -shared -o libddv3djava.so -lddvd3d com_ddv3d_Ddv3dBinding.o

如果未找到libddv3d.so，则可以使用-L标志添加额外的路径以进行搜索.

If libddv3d.so isn't found you can add extra path's to search using -L flag.

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