按键映射工具QKeyMapper，Qt开发Win10&Win11可用，不修改注册表、不需重新启动系统，可立即生效和停止

SingleApplication ================= This is a replacement of the QSingleApplication for `Qt5`. Keeps the Primary Instance of your Application and kills each subsequent instances. It can (if enabled) spawn a certain number of secondary instances (with the `--secondary` command line argument). Usage ----- The `SingleApplication` class inherits from whatever `Q[Core|Gui]Application` class you specify. Further usage is similar to the use of the `Q[Core|Gui]Application` classes. The library uses your `Organization Name` and `Application Name` to set up a `QLocalServer` and a `QSharedMemory` block. The first instance of your Application is your Primary Instance. It would check if the shared memory block exists and if not it will start a `QLocalServer` and then listen for connections on it. Each subsequent instance of your application would check if the shared memory block exists and if it does, it will connect to the QLocalServer to notify it that a new instance had been started, after which it would terminate with status code `0`. The Primary Instance, `SingleApplication` would emit the `showUp()` signal upon detecting that a new instance had been started. The library uses `stdlib` to terminate the program with the `exit()` function. Here is an example usage of the library: ```cpp // In your Project.pro DEFINES += QAPPLICATION_CLASS=QGuiApplication # QApplication is the default // main.cpp #include "singleapplication.h" int main( int argc, char* argv[] ) { QApplication::setApplicationName("{Your App Name}"); QApplication::setOrganizationName("{Your Organization Name}"); SingleApplication app( argc, argv ); return app.exec(); } ``` The `Show Up` signal ------------------------ The SingleApplication class implements a `showUp()` signal. You can bind to that signal to raise your application's window when a new instance had been started. Note that since `SingleApplication` extends the `QApplication` class you can do the following: ```cpp // window is a QWindow instance QObject::connect( &app, &SingleApplication::showUp, window, &QWindow::raise ); ``` Using `QApplication::instance()` is a neat way to get the `SingleApplication` instance anywhere in your program. Secondary Instances ------------------- If you want to be able to launch additional Secondary Instances (not related to your Primary Instance) you have to enable that with the third parameter of the `SingleApplication` constructor. The default is `0` meaning no Secondary Instances. Here is an example allowing spawning up to `2` Secondary Instances. ```cpp SingleApplication app( argc, argv, 2 ); ``` After which just call your program with the `--secondary` argument to launch a secondary instance. __*Note:*__ If your Primary Instance is terminated upon launch of a new one it will replace it as Primary even if the `--secondary` argument has been set. *P.S. If you think this behavior could be improved create an issue and explain why.* Implementation -------------- The library is implemented with a QSharedMemory block which is thread safe and guarantees a race condition will not occur. It also uses a QLocalSocket to notify the main process that a new instance had been spawned and thus invoke the `showUp()` signal. To handle an issue on `*nix` systems, where the operating system owns the shared memory block and if the program crashes the memory remains untouched, the library binds to the following signals and closes the program with error code = `128 + signum` where signum is the number representation of the signal listed below. Handling the signal is required in order to safely delete the `QSharedMemory` block. Each of these signals are potentially lethal and will results in process termination. * `SIGHUP` - `1`, Hangup. * `SIGINT` - `2`, Terminal interrupt signal * `SIGQUIT` - `3`, Terminal quit signal. * `SIGILL` - `4`, Illegal instruction. * `SIGABRT` - `6`, Process abort signal. * `SIGBUS` - `7`, Access to an undefined portion of a memory object. * `SIGFPE` - `8`, Erroneous arithmetic operation (such as division by zero). * `SIGSEGV` - `11`, Invalid memory reference. * `SIGSYS` - `12`, Bad system call. * `SIGPIPE` - `13`, Write on a pipe with no one to read it. * `SIGALRM` - `14`, Alarm clock. * `SIGTERM` - `15`, Termination signal. * `SIGXCPU` - `24`, CPU time limit exceeded. * `SIGXFSZ` - `25`, File size limit exceeded. License ------- This library and it's supporting documentation are released under `The MIT License (MIT)`.