#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;
}

————————————————
版权声明：本文为CSDN博主「libaineu2004」的原创文章，遵循CC 4.0 BY-SA版权协议，转载请附上原文出处链接及本声明。
原文链接：https://blog.csdn.net/libaineu2004/article/details/75035946

TEMPLATE = app
CONFIG += console c++11
CONFIG -= app_bundle
CONFIG -= qt
 
DESTDIR = ../bin
 
QMAKE_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 directory
LIBS += -L../bin/ -lslstrlen
 
SOURCES += main.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;
}

#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

#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