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SingleInstance

Opt-in primary/secondary guard (2.74).

import QWinUI3.Platform · src/platform/QWinUI3/Platform/SingleInstance.h

Category: Platform · Library: v2.80 · C++ type

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Extends QObject.

Example

Default is multi-instance. Enable with env QWINUI3_SINGLE_INSTANCE=1 or an
explicit tryBecomePrimary() call. Secondary processes forward argv to the
primary over QLocalSocket; the caller must exit when tryBecomePrimary returns false.

#include "SingleInstance.h"
QWinUI3::SingleInstance guard;
if (!guard.tryBecomePrimary(QStringLiteral("org.example.myapp")))
    return 0;
QObject::connect(&guard, &QWinUI3::SingleInstance::activationRequested,
                 [](const QStringList &args) { /* raise window */ });

API

Properties

Name Type Description
primary bool
serverName QString

Signals

Signature Description
activationRequested(const QStringList &args)
primaryChanged()
serverNameChanged()

Methods

Signature Description
isEnvOptIn()
tryBecomePrimary(const QString &serverName)
release()

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