在Qt中遇到“invalid nullptr parameter”错误通常是因为向函数传递了一个空指针(nullptr),而这个函数不接受空指针作为参数。 在Qt编程中,确保不向函数传递空指针是非常重要的,因为许多Qt函数和对象方法都不接受空指针作为有效参数。当传递了空指针时,程序可能会崩溃或抛出异常,并显示“invalid nullptr parameter”错误。
qWarning("QObject::connect(%s, %s): invalid nullptr parameter", senderString, receiverString); if (slotObj) slotObj->destroyIfLastRef(); return QMetaObject::Connection(); }//同QT4 QObject *s = const_cast<QObject *>(sender); QObject *r = const_cast<QObject *>(receiver); QOrderedMu...
signal) { qWarning("QObject::connect: invalid nullptr parameter"); if (slotObj) slotObj->destroyIfLastRef(); return QMetaObject::Connection(); } int signal_index = -1; void *args[] = { &signal_index, signal }; // 根据调用来判断是否存在信号,如果当前类没有就去父类中寻找 // 直到...
qCWarning(lcConnect,"QObject::connect: invalid nullptr parameter");if(slotObj) slotObj->destroyIfLastRef();returnQMetaObject::Connection(); }intsignal_index = -1;void*args[] = { &signal_index, signal };for(; senderMetaObject && signal_index <0; senderMetaObject = senderMetaObject->superC...
signal) { qWarning("QObject::connect: invalid null parameter"); if (slotObj) slotObj->destroyIfLastRef(); return QMetaObject::Connection(); } //2 信号索引检查其有效性 int signal_index = -1; void *args[] = { &signal_index, signal }; for (; senderMetaObject && signal_index < 0;...
首选项错误码:code:"401” err: Error: Parameter error. The type of 'value' must be ValueType. 如何排查问题 如何查看或导出持久化数据? 如何获知数据存储沙箱路径? 插入数据之后,RDB数据库的wal文件体积异常 用户首选项是线程安全的吗 为什么在关系型数据库中调用deleteRdbStore函数后并未真实删除数据...
OpenGLWidget(QWidget *parent = nullptr); ~OpenGLWidget(); void initializeGL() override; void resizeGL(int w, int h) override; void paintGL() override; private: QOpenGLShaderProgram m_shaderProgram; QOpenGLBuffer m_vertexBuffer; QOpenGLVertexArrayObject m_vao; }; 在这个示例中,我们创建了一个...
if (!signal) {qWarning("QObject::connect: invalid nullptr parameter");if (slotObj)slotObj->destroyIfLastRef();return QMetaObject::Connection();} 第二个片段是去找到信号发送者(sender)的元对象类型(Meta Object)以及信号在对象信号中的位置。如果当前对象没有该信号,就去其父类对象去找。直到找到为止...
); mqtt::token_ptr subtok = client_.subscribe(topic_.toStdString(), QOS,nullptr, cb_)...
QNetworkReply::ProxyNotFoundError103the proxy host name was not found (invalid proxy hostname) QNetworkReply::ProxyTimeoutError104the connection to the proxy timed out or the proxy did not reply in time to the request sent QNetworkReply::ProxyAuthenticationRequiredError105the proxy requires authenticati...