C++动态加载so/dll库的实现

#ifndef DLOAD_BASE_H
#define DLOAD_BASE_H
/**
 * 必须实现 moduleName_create 函数,来初始化对象
 * extern "C" Base *module1_create() {
 *     return new Module;
 * }
 *
 * //必须实现 moduleName_destroy 函数,来回收对象
 * extern "C" void module1_destroy(Base *obj) {
 *     delete obj;
 * }
 */
class Base {
 public:
  virtual std::string readLine(const std::string &) = 0;
  virtual ~Base() = default;
};
#endif //DLOAD_BASE_H

//简单的模块 例子
//转大写
#include <algorithm>
#include <string>
#include "../base.h"
class Module1 : public Base {
  std::string readLine(const std::string &str) override {
      std::string str2(str);
      std::transform(str.begin(), str.end(), str2.begin(), ::toupper);
      return str2;
  }
};
//必须实现 moduleName_create 函数,来初始化对象
extern "C" Base *module1_create() {
    return new Module1;
}
//必须实现 moduleName_destroy 函数,来回收对象
extern "C" void module1_destroy(Base *obj) {
    delete obj;
}

//声明创建对象的函数
typedef Base *(*create)();
//声明回收对象的函数
typedef void (*destroy)(Base *);
//调用系统函数,加载动态库
#ifdef _WIN32
HINSTANCE loadLib(Base **base, const char *path, const char *funName) {
    auto handle = LoadLibrary(path);
    if (!handle) {
        return nullptr;
    }
    auto cr = (create) GetProcAddress(handle, funName);
    if (cr) {
        *base = cr();
    }
    return handle;
}
//调用系统函数,卸载动态库
void freeLib(HINSTANCE handle, Base *obj, const char *funName) {
    auto free = (destroy) GetProcAddress(handle, funName);
    if (free) {
        free(obj);
    }
    FreeLibrary(handle);
}
#else
void *loadLib(Base **base, const char *path, const char *funName) {
    auto handle = dlopen(path, RTLD_LAZY);
    if (!handle) {
        return nullptr;
    }
    auto cr = (create) dlsym(handle, funName);
    if (cr) {
        *base = cr();
    }
    return handle;
}
//调用系统函数,卸载动态库
void freeLib(void *handle, Base *obj, const char *funName) {
    auto free = (destroy) dlsym(handle, funName);
    if (free) {
        free(obj);
    }
    dlclose(handle);
}
#endif

int main() {
    std::string libPath;
#ifdef _WIN32
    libPath = std::string("./module/libmodule1" + ".dll");
#else
    libPath = std::string("./module/libmodule1" + ".so");
#endif
    Base *module = nullptr;
    auto handle = loadLib(&module, libPath.c_str(), std::string("module1_create").c_str());
    if (!module) {
        std::cout << "load lib module1" << " fail" << std::endl;
        return 1;
    }
    std::cout << module->readLine("abc") << std::endl;
    return 0;
}