There are hundreds of built-in QtGobal the global definition, probably more than twenty commonly divided into Types Types, Functions function, Macros macro definitions, the code knock tired wave of consolidation study is necessary
Documents Address: https://doc.qt.io/qt-5/qtglobal.html#QFunctionPointer-typedef
table of Contents
1.QFunctionPointer
Pointer type, point with no parameters and returns a pointer to void function
2.QtMessageHandler
One kind of function pointers, pointing to the use of:
void myMessageHandler(QtMsgType, const QMessageLogContext &, const QString &);3.enum QtMsgType
This enumeration describes the message may be sent to the message handler (QtMessageHandler) can be used to identify this enumeration of various message types and associated with the appropriate operation.
4.
| qint8 | signed char |
| qint16 | signed short |
| qint32 | signed int |
| qint64 | long long int |
| qlonglong | long long int |
| qreal | double |
| qsizetype | ssize_t |
| quint8 | unsigned char |
| quint16 | unsigned short |
| quint32 | unsigned int |
| quint64 | unsigned long long int |
| qulonglong | unsigned long long int |
| flying | unsigned char |
| uint | unsigned int |
| ulong | unsigned long |
| ushort | unsigned short |
5.qintptr
Signed integer pointer
6.quintptr
Unsigned int pointer
7.qptrdiff
It represents integer type pointer difference
