M1 Mac上wxWidgets按钮绑定出现x86_64架构未定义符号错误

问题描述 #

在运行macOS Sonoma 14.4.1的M1 MacBook Pro上安装wxWidgets后，编译修改Hello World示例时，添加按钮绑定出现以下链接错误：

Undefined symbols for architecture x86_64:
  "MyFrame::onOkButton(wxCommandEvent&)", referenced from:
      MyFrame::MyFrame() in hello_tests-3e1e88.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

相关代码如下：

// Start of wxWidgets "Hello World" Program
#include <wx/wx.h>
#include <wx/button.h>


class MyApp : public wxApp
{
public:
    bool OnInit() override;
};

wxIMPLEMENT_APP(MyApp);

class MyFrame : public wxFrame
{
public:
    MyFrame();

private:
    void OnHello(wxCommandEvent& event);
    void OnExit(wxCommandEvent& event);
    void OnAbout(wxCommandEvent& event);
    void onOkButton(wxCommandEvent& event);
};

enum
{
    ID_Hello = 1
};

bool MyApp::OnInit()
{
    MyFrame *frame = new MyFrame();
    frame->Show(true);
    return true;
}

MyFrame::MyFrame()
    : wxFrame(nullptr, wxID_ANY, "Hello World")
{
    wxMenu *menuFile = new wxMenu;
    menuFile->Append(ID_Hello, "&Hello...\tCtrl-H",
                     "Help string shown in status bar for this menu item");
    menuFile->AppendSeparator();
    menuFile->Append(wxID_EXIT);

    wxMenu *menuHelp = new wxMenu;
    menuHelp->Append(wxID_ABOUT);

    wxMenuBar *menuBar = new wxMenuBar;
    menuBar->Append(menuFile, "&File");
    menuBar->Append(menuHelp, "&Help");

    SetMenuBar( menuBar );

    CreateStatusBar();
    SetStatusText("Welcome to wxWidgets!");

    //first attempt at adding a widget to the frame - SW 4/20/24
    //
    wxButton* myButton  = new wxButton(this, wxID_ANY, ("MyButton" ), wxPoint(10, 20), wxSize(80,30));


    Bind(wxEVT_MENU, &MyFrame::OnHello, this, ID_Hello);
    Bind(wxEVT_MENU, &MyFrame::OnAbout, this, wxID_ABOUT);
    Bind(wxEVT_MENU, &MyFrame::OnExit, this, wxID_EXIT);
    //Bind(wxEVT_BUTTON, &MyFrame::onOkButton);
    //myButton->Bind(wxEVT_BUTTON, &MyFrame::onOkButton, this);
}

void MyFrame::OnExit(wxCommandEvent& event)
{
    Close(true);
}

void MyFrame::OnAbout(wxCommandEvent& event)
{
    wxMessageBox("This is a wxWidgets Hello World example",
                 "About Hello World", wxOK | wxICON_INFORMATION);
}

void MyFrame::OnHello(wxCommandEvent& event)
{
    wxLogMessage("Hello world from wxWidgets!");
}

void onOkButton(wxCommandEvent& event)
{
    wxMessageBox("Button Test",
                 "About This App", wxOK | wxICON_INFORMATION);
}

问题原因 #

你在MyFrame类的私有成员中声明了onOkButton成员函数，但实现时没有加上MyFrame::作用域，导致这个函数被当成全局函数，而绑定代码引用的是MyFrame类的成员函数，链接器找不到对应的符号。

修复步骤 #

1. 修改onOkButton的实现，添加类作用域：

void MyFrame::onOkButton(wxCommandEvent& event)
{
    wxMessageBox("Button Test",
                 "About This App", wxOK | wxICON_INFORMATION);
}

2. 取消按钮绑定代码的注释，推荐使用按钮自身的Bind方式（逻辑更清晰）：

myButton->Bind(wxEVT_BUTTON, &MyFrame::onOkButton, this);

修改后重新编译，链接器就能找到MyFrame::onOkButton的定义，错误即可解决。

内容的提问来源于stack exchange，提问作者SJWoodward