Qt plugin identifier issue

[_eph]

Hi, I've got a Qt plugin which is static for iOS build but dynamic for other systems. This way the IID needs to be different.

#include <QtQuick>
#include <QtGlobal>

class myPlugin : public QQmlExtensionPlugin
{
	Q_OBJECT
#if defined(Q_OS_IOS)
    Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QQmlExtensionInterface/1.0")
#else
    Q_PLUGIN_METADATA(IID "myPlugin")
#endif

The problem is that on iOS it doesn't seem to be using the correct IID. I would get runtime error that myPlugin cannot be found.

1. I can confirm Q_OS_IOS is defined - when I use #pragma message to see which branch is being used I get the correct one.
2. When I comment out the conditions and leave just Q_PLUGIN_METADATA(IID "org.qt-project.Qt.QQmlExtensionInterface/1.0") the app works fine.
3. When I comment out only Q_PLUGIN_METADATA(IID "myPlugin") the code won't compile with

Undefined symbols for architecture arm64:
 "qt_static_plugin_myPlugin()", referenced from:
...

I'm baffled - it kind of looks like the compiler is using and not using the correct conditional branch at the same time :).

[sierdzio]

@_eph said in Qt plugin identifier issue:

I'm baffled - it kind of looks like the compiler is using and not using the correct conditional branch at the same time :).

Perhaps the interface is prepared by MOC (Meta Object Compiler) which is known to be quite dumb.

A few solutions:

• check the generated moc_*.h file - does it contain correct information?
• use 2 separate files for your plugin, one for iOS, one for remaining platforms
• have one plugin "template" (same file you have now, but a single replace line for metadata) then use QMAKE_SUBSTITUTES to dynamically generate proper plugin file during compilation