A null QString is an uninitialized QString while an empty QString is a QString initialized with an empty string(reference). QString s1; QString s2(“”); if(s1==s2) qDebug()<<“same”;//same else qDebug()<<“not same”; qDebug()<<s1.isNull();//true qDebug()<<s1.isEmpty();//true […]
QTexStream::readLine() function is a convenient function that can read a line from a file at a time. However, you must pay attention to so called new line. You may find […]
In this post, I talked about the best practice to use forward declaration or include file for a class: only include header files for base class and value member class […]
I used to putting all my code in one .cpp file. That is my style. Don’t be fooled by the “principles” and “theories” advocated by software engineering experts. Those “principles” […]
Today, I ran a program that connects to a database, then a window popped up: Meanwhile, the following error appeared on the console: QSqlDatabase: QMYSQL driver not loaded QSqlDatabase: available […]
You may wonder why the qmake CONFIG variable has values that you never set. Sometimes, you even need to remove some values from CONFIG in your .pro file using: CONFIG […]
You may never notice the interaction between Qt Creator and the GDB debugger in the past. The communication between Qt Creator and GDB is hidden well. You are supposed to […]
If you got an app that was built with Qt lib, how do you get the version of Qt? Suppose you only have the .exe file, you have not the […]
Qt Creator loads the GDB pretty printers in the following manner. First, it imports the gdbbridge module by running the following gdb command. python from gdbbridge import * The file […]
Some day, you may want to debug qmake, … for fun. How to debug qmake? In the source directory of qmake(c:\Qt5.12.1\5.12.1\Src\qtbase\qmake), you will find a .pro file qmake.pro, which would […]