whytofly
/
qt6-bb10
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Ignore WasDeclaredAsMetaType flag during binary check. 

Nobody should break ODR, but we were living with apps breaking it
for at least 8 years. Sure it is an undefined behavior but in many
cases it works. I do not think that Qt should enforce usage of
a proper C++, it is role of a tool chain. Qt can only indicate that
something is going terribly wrong.

Make message a bit more verbose. Sometimes the ODR violation is not
that easy to fix, therefore a hint is a nice addition.

Update documentation of qRegisterMetaType.

Change-Id: I61dcccc840eec80a4ed5b8a212a912807d239d8c
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
bb10
Jędrzej Nowacki 2013-01-03 11:06:21 +01:00 committed by The Qt Project
parent 700363c98c
commit 0421769e36
1 changed files with 31 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

36
src/corelib/kernel/qmetatype.cpp
View File

@ -646,11 +646,26 @@ int QMetaType::registerNormalizedType(const NS(QByteArray) &normalizedTypeName,
"size %i, now registering size %i.",
normalizedTypeName.constData(), idx, previousSize, size);
}
// Ignore WasDeclaredAsMetaType inconsitency, to many users were hitting the problem
previousFlags |= WasDeclaredAsMetaType;
flags |= WasDeclaredAsMetaType;
if (previousFlags != flags) {
qFatal("QMetaType::registerType: Binary compatibility break "
"-- Type flags for type '%s' [%i] don't match. Previously "
"registered TypeFlags(0x%x), now registering TypeFlags(0x%x).",
normalizedTypeName.constData(), idx, previousFlags, int(flags));
const int maskForTypeInfo = NeedsConstruction | NeedsDestruction | MovableType;
const char *msg = "QMetaType::registerType: Binary compatibility break. "
"\nType flags for type '%s' [%i] don't match. Previously "
"registered TypeFlags(0x%x), now registering TypeFlags(0x%x). "
"This is an ODR break, which means that your application depends on a C++ undefined behavior."
"\nHint: %s";
QT_PREPEND_NAMESPACE(QByteArray) hint;
if ((previousFlags & maskForTypeInfo) != (flags & maskForTypeInfo)) {
hint += "\nIt seems that the type was registered at least twice in a different translation units, "
"but Q_DECLARE_TYPEINFO is not visible from all the translations unit or different flags were used."
"Remember that Q_DECLARE_TYPEINFO should be declared before QMetaType registration, "
"preferably it should be placed just after the type declaration and before Q_DECLARE_METATYPE";
}
qFatal(msg, normalizedTypeName.constData(), idx, previousFlags, int(flags), hint.constData());
}
return idx;
@ -1722,6 +1737,9 @@ const QMetaObject *QMetaType::metaObjectForType(int type)
\snippet code/src_corelib_kernel_qmetatype.cpp 9
\warning This function is useful only for registering an alias (typedef)
for every other use case Q_DECLARE_METATYPE and qMetaTypeId() should be used instead.
\sa qRegisterMetaTypeStreamOperators(), QMetaType::isRegistered(),
Q_DECLARE_METATYPE()
*/
@ -1767,7 +1785,7 @@ const QMetaObject *QMetaType::metaObjectForType(int type)
*/
/*!
\fn int qRegisterMetaType(const char *typeName)
\fn int qRegisterMetaType()
\relates QMetaType
\threadsafe
\since 4.2
@ -1779,6 +1797,14 @@ const QMetaObject *QMetaType::metaObjectForType(int type)
\snippet code/src_corelib_kernel_qmetatype.cpp 7
This function requires that \c{T} is a fully defined type at the point
where the function is called. For pointer types, it also requires that the
pointed to type is fully defined. Use Q_DECLARE_OPAQUE_POINTER() to be able
to register pointers to forward declared types.
After a type has been registered, you can create and destroy
objects of that type dynamically at run-time.
To use the type \c T in QVariant, using Q_DECLARE_METATYPE() is
sufficient. To use the type \c T in queued signal and slot connections,
\c{qRegisterMetaType<T>()} must be called before the first connection