本文介绍了C ++共享库未定义引用`FooClass :: SayHello()'的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我在制作一个C ++共享库,当我编译一个主exe,使用编译器给我的库:
I'm making a C++ Shared Library and when I compile a main exe that uses the library the compiler gives me:
main.cpp:(.text+0x21): undefined reference to `FooClass::SayHello()'
collect2: ld returned 1 exit status
图书馆代码:
fooclass.h
fooclass.h
#ifndef __FOOCLASS_H__
#define __FOOCLASS_H__
class FooClass
{
public:
char* SayHello();
};
#endif //__FOOCLASS_H__
fooclass.cpp
fooclass.cpp
#include "fooclass.h"
char* FooClass::SayHello()
{
return "Hello Im a Linux Shared Library";
}
编译:
g++ -shared -fPIC fooclass.cpp -o libfoo.so
Main:
main.cpp
Main:main.cpp
#include "fooclass.h"
#include <iostream>
using namespace std;
int main(int argc, char const *argv[])
{
FooClass * fooClass = new FooClass();
cout<< fooClass->SayHello() << endl;
return 0;
}
编译:
g++ -I. -L. -lfoo main.cpp -o main
机器是Ubuntu Linux 12
The machine is an Ubuntu Linux 12
谢谢!
推荐答案
g++ -I. -L. -lfoo main.cpp -o main
是问题。最近的GCC版本要求您按照它们相互依赖的顺序放置对象文件和库 - 作为一个相应的经验法则,您必须将库标志作为链接器的最后一个开关;一世。 e。写
is the problem. Recent versions of GCC require that you put the object files and libraries in the order that they depend on each other - as a consequential rule of thumb, you have to put the library flags as the last switch for the linker; i. e., write
g++ -I. -L. main.cpp -o main -lfoo
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