The QSocketNotifier class provides support for monitoring activity on a file descriptor. 更多...
| 头： | #include <QSocketNotifier> |
| qmake: | QT += core |
| 继承： | QObject |
| enum | Type { Read, Write, Exception } |
| QSocketNotifier (qintptr socket , QSocketNotifier::Type type , QObject * parent = nullptr) | |
| virtual | ~QSocketNotifier () |
| bool | isEnabled () const |
| qintptr | socket () const |
| QSocketNotifier::Type | type () const |
| void | setEnabled (bool enable ) |
| void | activated (int socket ) |
| const QMetaObject | staticMetaObject |
| virtual bool | event (QEvent * e ) override |
The QSocketNotifier class provides support for monitoring activity on a file descriptor.
The QSocketNotifier makes it possible to integrate Qt's event loop with other event loops based on file descriptors. File descriptor action is detected in Qt's main event loop ( QCoreApplication::exec ()).
Once you have opened a device using a low-level (usually platform-specific) API, you can create a socket notifier to monitor the file descriptor. The socket notifier is enabled by default, i.e. it emits the activated () signal whenever a socket event corresponding to its type occurs. Connect the activated () signal to the slot you want to be called when an event corresponding to your socket notifier's type occurs.
There are three types of socket notifiers: read, write, and exception. The type is described by the Type enum, and must be specified when constructing the socket notifier. After construction it can be determined using the type () function. Note that if you need to monitor both reads and writes for the same file descriptor, you must create two socket notifiers. Note also that it is not possible to install two socket notifiers of the same type ( 读取 , 写入 , Exception ) on the same socket.
The setEnabled () function allows you to disable as well as enable the socket notifier. It is generally advisable to explicitly enable or disable the socket notifier, especially for write notifiers. A disabled notifier ignores socket events (the same effect as not creating the socket notifier). Use the isEnabled () 函数以确定通知的当前状态。
最后，可以使用 socket () function to retrieve the socket identifier. Although the class is called QSocketNotifier , it is normally used for other types of devices than sockets. QTcpSocket and QUdpSocket provide notification through signals, so there is normally no need to use a QSocketNotifier on them.
另请参阅 QFile , QProcess , QTcpSocket ，和 QUdpSocket .
此枚举描述套接字通知程序可以识别的各种类型的事件。必须指定类型当构造套接字通知程序时。
Note that if you need to monitor both reads and writes for the same file descriptor, you must create two socket notifiers. Note also that it is not possible to install two socket notifiers of the same type (Read, Write, Exception) on the same socket.
| 常量 | 值 | 描述 |
|---|---|---|
QSocketNotifier::Read
|
0
|
有数据要读取。 |
QSocketNotifier::Write
|
1
|
数据可以被写入。 |
QSocketNotifier::Exception
|
2
|
发生异常。建议不要使用此。 |
另请参阅 QSocketNotifier () 和 type ().
构造套接字通知程序采用给定 parent . It enables the socket , and watches for events of the given type .
It is generally advisable to explicitly enable or disable the socket notifier, especially for write notifiers.
Windows 用户注意： The socket passed to QSocketNotifier will become non-blocking, even if it was created as a blocking socket.
另请参阅 setEnabled () 和 isEnabled ().
[虚拟]
QSocketNotifier::
~QSocketNotifier
()
销毁此套接字通知程序。
[signal]
void
QSocketNotifier::
activated
(
int
socket
)
此信号被发射每当套接字通知程序被启用时，且套接字事件对应 type 出现。
套接字标识符被传入 socket 参数。
注意： 这是私有信号。它可以用于信号连接，但不能由用户发射。
[override virtual protected]
bool
QSocketNotifier::
event
(
QEvent
*
e
)
重实现自 QObject::event ().
返回
true
若通知被启用；否则返回
false
.
另请参阅 setEnabled ().
[slot]
void
QSocketNotifier::
setEnabled
(
bool
enable
)
若 enable 为 true，通知被启用；否则通知被禁用。
通知默认是启用的，即，它发射 activated () signal whenever a socket event corresponding to its type occurs. If it is disabled, it ignores socket events (the same effect as not creating the socket notifier).
Write notifiers should normally be disabled immediately after the activated () signal has been emitted
另请参阅 isEnabled () 和 activated ().
Returns the socket identifier specified to the constructor.
另请参阅 type ().
Returns the socket event type specified to the constructor.
另请参阅 socket ().