Linux之共享库封装、使用的典型demo-白红宇

Linux之共享库封装、使用的典型demo

阅读量：4025 次

发布时间：2019-05-24

本文共 3162 字，大约阅读时间需要 10 分钟。

## 目录结构

main.cpp

device.h

lib | ev | libdevice.so

| hw | libdevice.so

| kt | libdevice.so

device | device.h evoc_device.cpp hw_device.cpp kt_device.cpp

| hw_lib | hw.c hw.h

## 生成静态库（模拟第三方提供的静态库）

#include "hw.h"int calcCpuRate(){        return 90;}int calcTemp(){        return 100;}

#ifndef HW_H#define HW_Hint calcCpuRate();int calcTemp();#endif

gcc -c hw.c

ar -rc libhw.a hw.o

## 基于静态库生成自己统一接口的共享库

#ifndef DEVICE_H#define DEVICE_H#include 
   
    using namespace std;class Device {public:        Device(){}        virtual int getTemp(){}        virtual int getCpuRate(){}        virtual int getHeight(){}        virtual string getDiskInfo(){}};#endif

#include "device.h"#include 
   
    class EVoc_Device : public Device {public:        EVoc_Device():Device(){                cout << "This is Evoc Device...." << endl;                m_temp = 50;                m_cpuRate = 10;                m_height = 20;                m_diskInfo = "well";        }        virtual int getTemp(){                return m_temp;        }        virtual int getCpuRate(){                return m_cpuRate;        }        virtual int getHeight(){                return m_height;        }        virtual string getDiskInfo(){                return m_diskInfo;        }private:        int m_temp;        int m_cpuRate;        int m_height;        string m_diskInfo;};extern "C" Device * create(){        return (new EVoc_Device());}

TARGET  = libdevice.soCC      = gccCXX     = g++LDFLAG  = -shared -fPICxx:        @echo $(DEV)ifeq ($(DEV),EVOC)        $(CXX) $(LDFLAG) -o $(TARGET) evoc_device.cppendififeq ($(DEV),KONTRON)        $(CXX) $(LDFLAG) -o $(TARGET) kontron_device.cppendififeq ($(DEV),HUAWEI)        $(CXX) $(LDFLAG) -o $(TARGET) huawei_device.cpp -I./hw_lib -L./hw_lib -lhwendif

make DEV=EVOC

生成libdevice.so

## 调度共享库

#include "device.h"#include 
   
    #include 
    
     #include 
     
      #include 
      
       #include 
       
        using namespace std;#define DEV_PATH_LEN 20int main(int argc,char **argv){        char * pDevType = NULL;        if (argc >= 2)                pDevType = argv[1];        else                pDevType = "hw";        char devPath[DEV_PATH_LEN];        memset(devPath ,0,DEV_PATH_LEN);        sprintf(devPath,"./lib/%s/libdevice.so",pDevType);        typedef Device * (*Device_t)();        void * dev_handler = dlopen(devPath ,RTLD_LAZY);        if (!dev_handler){                cout << "Cannot load library: " << dlerror() << '\n';                return 0;        }        dlerror();        Device_t create_method = (Device_t)dlsym(dev_handler,"create");        const char * dlsym_error = dlerror();         if (dlsym_error) {        cerr << "Cannot load symbol create: " << dlsym_error << '\n';        return 1;    }    Device * pDevice = create_method();        if (pDevice){                cout << "Temp:\t" << pDevice->getTemp() << endl;                cout << "Height:\t" << pDevice->getHeight() << endl;                cout << "CpuRate:\t" << pDevice->getCpuRate() << endl;                cout << "DiskInfo:\t" << pDevice->getDiskInfo() << endl;        }        return 0;}