訪問共享庫時沒有可用的源代碼錯誤

Question

我的Eclipse IDE中有兩個項目。我的操作系統是Ubuntu。一個是應用程序項目，另一個是共享lib項目。我已經鏈接了link中討論的所有路徑和庫要求。但是當我調試時，我得到錯誤No source available for "0x0"。當我訪問共享庫對象時，該錯誤發生在iOCR* pOCR = (iOCR*)create();。我的鏈接有什麼問題？ 附上我的共享庫代碼和應用程​​序代碼。

共用資料庫頭文件

#ifndef OCR_DLL_H_ 
#define OCR_DLL_H_  
#include <opencv/cv.h> 
#include <opencv2/highgui/highgui.hpp> 
#include <opencv2/imgproc/imgproc.hpp> 
#include <tesseract/baseapi.h> 
#include <iostream> 
#include "Define.h"  

using namespace cv; 

namespace VIDEOANALYTICS_PLATFORM { 
    class iOCR{  
     public: 
      virtual ~iOCR(){} 
      virtual int preProcessing(Mat &img) = 0; 
      virtual int textExtraction(Mat &img) = 0; 
    };  
    class OCR : public iOCR{  
     public: 
      OCR(){} 
      ~OCR(){ ; } 
      int preProcessing(Mat &img); 
      int textExtraction(Mat &img); 
     private:  
    };  
} 

#endif /* OCR_DLL_H_ */ 

共用資料庫CPP

#include "OCR_dll.h" 

namespace VIDEOANALYTICS_PLATFORM { 
    extern "C" iOCR* create_object(){ 
     iOCR *p = new OCR(); 
     return p; 
    } 

    extern "C" void destroy_object(iOCR* object) 
    { 
     delete object; 
    } 

    int OCR::preProcessing(Mat &img){ 


     return SUCCESS; 
    } 

    int OCR::textExtraction(Mat &img){ 


     return SUCCESS; 
    } 
} 

應用的main.cpp

#include <stdio.h> 
#include "OCR_dll.h" 

#define SUCCESS 0 
#define FILE_ERROR 1 
#define HTTP_ERROR 2 
#define THREAD_ERROR 3 

using namespace VIDEOANALYTICS_PLATFORM; 
using namespace cv; 

void *readImage(void *ptr); 
void *postHTTP(void *ptr); 
int main(int argc, char *argv[]) 
{ 

    // on Linux, use "./myclass.so" 
     void* handle = dlopen("OCR.so", RTLD_LAZY); 

     iOCR* (*create)(); 
     void (*destroy)(iOCR*); 

     create = (iOCR* (*)())dlsym(handle, "create_object"); 
     destroy = (void (*)(iOCR*))dlsym(handle, "destroy_object"); 

     iOCR* pOCR = (iOCR*)create(); 

     if(pOCR){ 

      destroy(pOCR); 
     }//if(pOCR) 

     dlclose(handle); 
     return 0; 
} 

我與objdumb選中並且輸出作爲遵循

cdc@cdc-desktop:~/workspace/OCR/Debug$ objdump -TC libOCR.so 

libOCR.so:  file format elf32-i386 

DYNAMIC SYMBOL TABLE: 
00000000  DF *UND* 00000000 GLIBC_2.1.3 __cxa_atexit 
00000000 w D *UND* 00000000    __gmon_start__ 
00000000 w D *UND* 00000000    _Jv_RegisterClasses 
00000000  DF *UND* 00000000 GLIBCXX_3.4 operator delete(void*) 
00000000  DF *UND* 00000000 GLIBCXX_3.4 std::ios_base::Init::Init() 
00000000  DF *UND* 00000000 GLIBCXX_3.4 std::ios_base::Init::~Init() 
00000000 w D *UND* 00000000    _ITM_deregisterTMCloneTable 
00000000 w D *UND* 00000000    _ITM_registerTMCloneTable 
00000000  DO *UND* 00000000 CXXABI_1.3 vtable for __cxxabiv1::__class_type_info 
00000000  DF *UND* 00000000 CXXABI_1.3 __cxa_pure_virtual 
00000000  DF *UND* 00000000 GLIBCXX_3.4 operator new(unsigned int) 
00000000  DO *UND* 00000000 CXXABI_1.3 vtable for __cxxabiv1::__si_class_type_info 
00000000 w DF *UND* 00000000 GLIBC_2.1.3 __cxa_finalize 
00000c95 g DF .text 00000020 Base  destroy_object 
00000dc4 w DF .text 0000001e Base  VIDEOANALYTICS_PLATFORM::OCR::~OCR() 
00000de4 g DF .fini 00000000 Base  _fini 
00000d94 w DF .text 00000030 Base  VIDEOANALYTICS_PLATFORM::OCR::~OCR() 
00000d94 w DF .text 00000030 Base  VIDEOANALYTICS_PLATFORM::OCR::~OCR() 
00000d4c w DF .text 0000001e Base  VIDEOANALYTICS_PLATFORM::iOCR::~iOCR() 
00000cc0 g DF .text 0000000a Base  VIDEOANALYTICS_PLATFORM::OCR::textExtraction(cv::Mat&) 
00000d78 w DF .text 0000001c Base  VIDEOANALYTICS_PLATFORM::OCR::OCR() 
00000aec g DF .init 00000000 Base  _init 
00000e40 w DO .rodata 00000020 Base  typeinfo name for VIDEOANALYTICS_PLATFORM::OCR 
00000d78 w DF .text 0000001c Base  VIDEOANALYTICS_PLATFORM::OCR::OCR() 
00003018 g D .bss 00000000 Base  __bss_start 
00000d26 w DF .text 00000025 Base  VIDEOANALYTICS_PLATFORM::iOCR::~iOCR() 
00000d6a w DF .text 0000000e Base  VIDEOANALYTICS_PLATFORM::iOCR::iOCR() 
00000d26 w DF .text 00000025 Base  VIDEOANALYTICS_PLATFORM::iOCR::~iOCR() 
0000301c g D .bss 00000000 Base  _end 
00000e18 w DO .rodata 00000018 Base  vtable for VIDEOANALYTICS_PLATFORM::iOCR 
00000e30 w DO .rodata 0000000c Base  typeinfo for VIDEOANALYTICS_PLATFORM::OCR 
00000d6a w DF .text 0000000e Base  VIDEOANALYTICS_PLATFORM::iOCR::iOCR() 
00000cb6 g DF .text 0000000a Base  VIDEOANALYTICS_PLATFORM::OCR::preProcessing(cv::Mat&) 
00000e00 w DO .rodata 00000018 Base  vtable for VIDEOANALYTICS_PLATFORM::OCR 
00003018 g D .data 00000000 Base  _edata 
00000e84 w DO .rodata 00000008 Base  typeinfo for VIDEOANALYTICS_PLATFORM::iOCR 
00000c6c g DF .text 00000029 Base  create_object 
00000e60 w DO .rodata 00000021 Base  typeinfo name for VIDEOANALYTICS_PLATFORM::iOCR 

Answer 1

我看到有兩個可能的問題。

第一個是，爲此我只能猜測，您將共享對象放入與加載共享對象的可執行文件相同的路徑中，並且認爲dlopen會在進程當前目錄中顯示。 The manual page說

如果filename包含一個斜槓（「/」），那麼它被解釋爲（相對或絕對）路徑名。否則，動態鏈接程序按如下搜索庫：

然後它列出函數將在哪裏查找共享對象，其中包括/usr/lib。

如果該庫不在dlopen查找的路徑中，則將找不到該共享對象。

第一個問題的簡單解決方案是使用絕對路徑或相對路徑，例如，

dlopen("./OCR.so", RTLD_LAZY); 

這將在進程當前目錄（可能與可執行程序所在的目錄不同）中查找。

第二個問題是您命名了共享對象libOCR.so，並且您要求dlopen查找OCR.so。在查找文件時，dlopen不會自動添加lib前綴，您需要提供共享對象的實際文件名。