Qt中使用emit发送信号编译报错undefined reference to 'xxx' 考虑是在构建类时忘记加入Q_OBJECT。 重新加入Q_OBJECT又编译报错undefined reference to 'vtable for (类名)' qmake以后成功编译。 https://blog.csdn.net/wangzhiqian7hao/article/details/83446696 学习了一下。
E:\source\QT\qt_test\\centerthread.cpp:58: error: undefined reference to `centerThread::showMsg(int)' win 7 32bit Qt版本:3.1.1 结果(已解决,过程如下): 最后解决了,参照一楼说的,qmake并没有报错,估计是编译连接的问题,我把emit语句写在函数里,直接在头文件里面定义里实现这个函数就没问题了。
QT += core gui QT += multimediawidgets QT += xml QT += multimedia QT += network QT += widgets QT += serialport greaterThan(QT_MAJOR_VERSION, 4): QT += widgets CONFIG += c++11 # The following define makes your compiler emit warnings if you use # any Qt feature that has been ...
The ISO C++ Standard specifies that all virtualmethodsof a class that are not pure-virtual must be defined, but does not require any diagnostic for violations of this rule [class.virtual]/8. Based on thisassumption, GCC will only emit the implicitly defined constructors, the assignment operator...
简介:QT5在windows下调用OpenCV库出现: undefined reference to `xxxxx' 错误解决办法(适用MinGW编译器)。 一、环境介绍 window系统:win10 X64 QT版本: 5.12 QT5.12自带的MinGW编译器版本:mingw730_32 与mingw730_64 在QT的安装目录下,可以查看MinGW编译器的版本: ...
qt undefined reference to `vtable for subClass' 1. 建立一个console工程 QT -=gui CONFIG+= c++11console CONFIG-=app_bundle # The following define makes your compiler emit warningsifyou use # any feature of Qtwhichas been marked deprecated (the exact warnings...
当一个信号发出时,连接到它的槽函数通常会立即执行,就像一般的函数调用一样。当这种情况发生时,信号槽机制完全独立于任何的GUI事件循环。一旦所有的槽函数返回,emit语句后的代码就会执行。当使用连接队列时,情况有微小不同,emit关键字后的代码会立即继续执行,槽函数会稍后执行。
void Counter::setValue(int value) { if (value != m_value) { m_value = value; emit valueChanged(value); } } emit行发送valueChanged信号,参数是新的value。 下面的代码段,我们创建了两个Counter实例,使用QObject::connect连接第一个对象的valueChaged()信号到第二个对象的setValue槽。 Counter a,...
release/widget.o:widget.cpp:(.text+0x631):undefinedreferenceto`cv::fastFree(void*)' release/widget.o:widget.cpp:(.text+0x63b):undefinedreferenceto`cv::_OutputArray::_OutputArray(cv::Mat&)' release/widget.o:widget.cpp:(.text+0x64b):undefinedreferenceto`cv::_InputArray::_InputArray(cv:...
The ISO C++ Standard specifies that all virtual methods of a class that are not pure-virtual must be defined, but does not require any diagnostic for violations of this rule [class.virtual]/8. Based on this assumption, GCC will only emit the implicitly defined constructors, the assignment op...