Linux qtcreator编程实现动态加载动态链接库

完整的工程源码可以访问下载：http://download.csdn.net/download/libaineu2004/9896700

一、主程序main.cpp

#include <iostream>#include <dlfcn.h>using namespace std;typedef int (*pStrLenFun)(char *str);typedef char *(*pStrCopyFun)(char *desc, char *src);int main(int argc, char *argv[]){    char src[]="Hello Dymatic";    char desc[80];    pStrLenFun fun1;    pStrCopyFun fun2;    void *phandle = NULL;    char *perr = NULL;    phandle = dlopen("libslstrlen.so", RTLD_LAZY);//RTLD_NOW    if(!phandle)    {        printf("Failed Load library!\n");    }    perr = dlerror();    if(perr != NULL)    {        printf("%s\n",perr);        return 0;    }    fun1 = (pStrLenFun)dlsym(phandle, "StrLen");    perr = dlerror();    if(perr != NULL)    {        printf("%s\n",perr);        return 0;    }    fun2 = (pStrCopyFun)dlsym(phandle, "StrCopy");    perr = dlerror();    if(perr != NULL)    {        printf("%s\n",perr);        return 0;    }    printf("The string is: %s\n",src);    printf("the string length is: %d\n",fun1(src));    printf("the string copyed:%s\n",fun2(desc,src));    return 0;}

相应的go.pro文件

TEMPLATE = appCONFIG += console c++11CONFIG -= app_bundleCONFIG -= qtDESTDIR = ../binQMAKE_LFLAGS += -ldl #编译选项，否则会失败。comile option,dlopen()#如果程序员想在QtCretor直接运行并动态加载动态库的话，则需要添加好该库，否则会报错。#Failed Load library!#libslstrlen.so: cannot open shared object file: No such file or directoryLIBS += -L../bin/ -lslstrlenSOURCES += main.cpp

二、动态库

源文件slstrlen.cpp

#include "slstrlen.h"#define ENDSTRING '\0'int StrLen(char *string){  int len = 0;  while(*string++ != ENDSTRING)    len++;  return len;}char *StrCopy(char *desc, char *src){    return 0;}

头文件slstrlen.h

#ifndef SLSTRLEN_H#define SLSTRLEN_H#include "slstrlen_global.h"//如果动态库使用g++编译，那么动态库定义函数的时候加上extern "C"，否则会提示undefined symbol错误。extern "C" int SLSTRLENSHARED_EXPORT StrLen(char *string);extern "C" char * SLSTRLENSHARED_EXPORT StrCopy(char *desc, char *src);#endif // SLSTRLEN_H

头文件slstrlen_global.h

#ifndef SLSTRLEN_GLOBAL_H#define SLSTRLEN_GLOBAL_H//#include <QtCore/qglobal.h>#define Q_DECL_EXPORT     __attribute__((visibility("default")))#define Q_DECL_IMPORT     __attribute__((visibility("default")))#define Q_DECL_HIDDEN     __attribute__((visibility("hidden")))#if defined(SLSTRLEN_LIBRARY)#  define SLSTRLENSHARED_EXPORT Q_DECL_EXPORT#else#  define SLSTRLENSHARED_EXPORT Q_DECL_IMPORT#endif#endif // SLSTRLEN_GLOBAL_H

slstrlen.pro文件

#-------------------------------------------------## Project created by QtCreator 2017-07-12T14:58:54##-------------------------------------------------QT       -= core guiTARGET = slstrlenTEMPLATE = libDESTDIR = ../binDEFINES += SLSTRLEN_LIBRARY# The following define makes your compiler emit warnings if you use# any feature of Qt which as been marked as deprecated (the exact warnings# depend on your compiler). Please consult the documentation of the# deprecated API in order to know how to port your code away from it.DEFINES += QT_DEPRECATED_WARNINGS# You can also make your code fail to compile if you use deprecated APIs.# In order to do so, uncomment the following line.# You can also select to disable deprecated APIs only up to a certain version of Qt.#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0SOURCES += slstrlen.cppHEADERS += slstrlen.h\        slstrlen_global.hunix {    target.path = /usr/lib    INSTALLS += target}