昨天我遇到了痛苦，这让我沮丧了 24 小时。问题归结为随机发生的意外崩溃。更复杂的是，调试报告也有绝对随机的模式。更复杂的是，所有调试跟踪都导致随机Qt 源或本地 DLL，即每次都证明问题不在我这边。
这里有一些这样可爱的报告的例子：
Program received signal SIGSEGV, Segmentation fault.
0x0000000077864324 in ntdll!RtlAppendStringToString () from C:\Windows\system32\ntdll.dll
(gdb) bt
#0 0x0000000077864324 in ntdll!RtlAppendStringToString () from C:\Windows\system32\ntdll.dll
#1 0x000000002efc0230 in ?? ()
#2 0x0000000002070005 in ?? ()
#3 0x000000002efc0000 in ?? ()
#4 0x000000007787969f in ntdll!RtlIsValidHandle () from C:\Windows\system32\ntdll.dll
#5 0x0000000000000000 in ?? ()
warning: HEAP: Free Heap block 307e5950 modified at 307e59c0 after it was freed
Program received signal SIGTRAP, Trace/breakpoint trap.
0x00000000778bf0b2 in ntdll!ExpInterlockedPopEntrySListFault16 () from C:\Windows\system32\ntdll.dll
(gdb) bt
#0 0x00000000778bf0b2 in ntdll!ExpInterlockedPopEntrySListFault16 () from C:\Windows\system32\ntdll.dll
#1 0x000000007786fd34 in ntdll!RtlIsValidHandle () from C:\Windows\system32\ntdll.dll
#2 0x0000000077910d20 in ntdll!RtlGetLastNtStatus () from C:\Windows\system32\ntdll.dll
#3 0x00000000307e5950 in ?? ()
#4 0x00000000307e59c0 in ?? ()
#5 0x00000000ffffffff in ?? ()
#6 0x0000000000220f10 in ?? ()
#7 0x0000000077712d60 in WaitForMultipleObjectsEx () from C:\Windows\system32\kernel32.dll
#8 0x0000000000000000 in ?? ()
Program received signal SIGSEGV, Segmentation fault.
0x0000000000a9678a in QBasicAtomicInt::ref (this=0x8) at ../../include/QtCore/../../../qt-src/src/corelib/arch/qatomic_x86_64.h:121
121 : "memory");
(gdb) bt
#0 0x0000000000a9678a in QBasicAtomicInt::ref (this=0x8) at ../../include/QtCore/../../../qt-src/src/corelib/arch/qatomic_x86_64.h:121
#1 0x00000000009df08e in QVariant::QVariant (this=0x21e4d0, p=...) at d:/Distributions/qt-src/src/corelib/kernel/qvariant.cpp:1426
#2 0x0000000000b4dde9 in QList<QVariant>::value (this=0x323bd480, i=1) at ../../include/QtCore/../../../qt-src/src/corelib/tools/qlist.h:666
#3 0x00000000009ccff7 in QObject::property (this=0x3067e900,
name=0xa9d042a <QCDEStyle::drawPrimitive(QStyle::PrimitiveElement, QStyleOption const*, QPainter*, QWidget const*) const::pts5+650> "_q_stylerect")
at d:/Distributions/qt-src/src/corelib/kernel/qobject.cpp:3742
#4 0x0000000000000000 in ?? ()
正如您所看到的，这些东西非常讨厌，它没有提供任何有用的信息。但是，有一件事我没有注意。这是编译期间的一个奇怪的警告，也很难用眼睛捕捉到：
In file included from d:/Libraries/x64/MinGW-w64/4.7.2/Qt/4.8.4/include/QtCore/qsharedpointer.h:50:0,
from d:/Libraries/x64/MinGW-w64/4.7.2/Qt/4.8.4/include/QtCore/QSharedPointer:1,
from ../../../../source/libraries/Project/sources/Method.hpp:4,
from ../../../../source/libraries/Project/sources/Slot.hpp:4,
from ../../../../source/libraries/Project/sources/Slot.cpp:1:
d:/Libraries/x64/MinGW-w64/4.7.2/Qt/4.8.4/include/QtCore/qsharedpointer_impl.h: In instantiation of 'static void QtSharedPointer::ExternalRefCount<T>::deref(QtSharedPointer::ExternalRefCount<T>::Data*, T*) [with T = Project::Method::Private; QtSharedPointer::ExternalRefCount<T>::Data = QtSharedPointer::ExternalRefCountData]':
d:/Libraries/x64/MinGW-w64/4.7.2/Qt/4.8.4/include/QtCore/qsharedpointer_impl.h:336:11: required from 'void QtSharedPointer::ExternalRefCount<T>::deref() [with T = Project::Method::Private]'
d:/Libraries/x64/MinGW-w64/4.7.2/Qt/4.8.4/include/QtCore/qsharedpointer_impl.h:401:38: required from 'QtSharedPointer::ExternalRefCount<T>::~ExternalRefCount() [with T = Project::Method::Private]'
d:/Libraries/x64/MinGW-w64/4.7.2/Qt/4.8.4/include/QtCore/qsharedpointer_impl.h:466:7: required from here
d:/Libraries/x64/MinGW-w64/4.7.2/Qt/4.8.4/include/QtCore/qsharedpointer_impl.h:342:21: warning: possible problem detected in invocation of delete operator: [enabled by default]
d:/Libraries/x64/MinGW-w64/4.7.2/Qt/4.8.4/include/QtCore/qsharedpointer_impl.h:337:28: warning: 'value' has incomplete type [enabled by default]
实际上，我只是将这个警告作为最后的手段，因为在如此绝望地寻找错误的过程中，代码已经感染了字面上的日志死亡。
仔细阅读后，我想起了，例如，如果使用std::unique_ptr或std::scoped_ptr用于Pimpl - 肯定应该提供析构函数，否则代码甚至无法编译。但是，我还记得它std::shared_ptr不关心析构函数并且没有它也可以正常工作。这也是我没有注意这个奇怪警告的另一个原因。长话短说，当我添加析构函数时，这种随机崩溃停止了。看起来 QtQSharedPointer与std::shared_ptr. 我想如果 Qt 开发人员将此警告转化为错误会更好，因为这样的调试马拉松根本不值得花时间、精力和精力。
我的问题是：
- 有什么问题
QSharedPointer？为什么析构函数如此重要？ - 为什么在没有析构函数的情况下会发生崩溃？这些对象（使用Pimpl +
QSharedPointer）是在堆栈上创建的，并且在它们死后没有其他对象可以访问它们。然而，坠机发生在他们死后的某个随机时间段内。 - 有没有人遇到过这样的问题？请分享你的经验。
- Qt 中是否还有其他类似的陷阱——我必须知道这些陷阱以确保将来保持安全？
希望这些问题和我的一般帖子能帮助其他人避免我过去 24 小时去过的地狱。