qt-creator/share/qtcreator/templates/wizards/qtcreatorplugin/myplugin.h

#ifndef %PluginName:u%_%CppHeaderSuffix:u%
#define %PluginName:u%_%CppHeaderSuffix:u%

#include "%PluginName:l%_global.%CppHeaderSuffix%"

#include <extensionsystem/iplugin.h>

namespace %PluginName% {
namespace Internal {

class %PluginName%Plugin : public ExtensionSystem::IPlugin
{
    Q_OBJECT

public:
    %PluginName%Plugin();
    ~%PluginName%Plugin();

    bool initialize(const QStringList &arguments, QString *errorString);
    void extensionsInitialized();
    ShutdownFlag aboutToShutdown();

private slots:
    void triggerAction();
};

} // namespace Internal
} // namespace %PluginName%

#endif // %PluginName:u%_%CppHeaderSuffix:u%