QSet: ошибка с qHash и пользовательским классом
Я хочу создать QSet<Tag> что я хочу использовать внутри моей программы. Tag это мой пользовательский класс.
Когда я строю код, я получаю ошибки GCC, касающиеся qHash перегрузка:
Exercise.cpp.o
In file included from /opt/Qt/5.5/gcc_64/include/QtCore/qglobal.h:74:0,
from /opt/Qt/5.5/gcc_64/include/QtCore/qchar.h:37,
from /opt/Qt/5.5/gcc_64/include/QtCore/qstring.h:41,
from /opt/Qt/5.5/gcc_64/include/QtCore/QString:1,
from /src/wmathtest/LaTeXText.h:4,
from /src/wmathtest/Exercise.h:4,
from /src/wmathtest/Exercise.cpp:1:
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h: In instantiation of ‘uint qHash(const T&, uint) [with T = WMathTest::Tag; uint = unsigned int]’:
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:952:32: required from ‘QHash<Key, T>::Node** QHash<Key, T>::findNode(const Key&, uint*) const [with Key = WMathTest::Tag; T = QHashDummyValue; QHash<Key, T>::Node = QHashNode<WMathTest::Tag, QHashDummyValue>; uint = unsigned int]’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:808:36: required from ‘QHash<Key, T>::iterator QHash<Key, T>::insert(const Key&, const T&) [with Key = WMathTest::Tag; T = QHashDummyValue]’
/opt/Qt/5.5/gcc_64/include/QtCore/qset.h:188:94: required from ‘QSet<T>::iterator QSet<T>::insert(const T&) [with T = WMathTest::Tag]’
/src/wmathtest/Exercise.cpp:22:22: required from here
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:103:5: error: no matching function for call to ‘qHash(const WMathTest::Tag&)’
Q_DECL_NOEXCEPT_EXPR(noexcept(qHash(t)))
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:103:5: note: candidates are:
In file included from /opt/Qt/5.5/gcc_64/include/QtCore/qset.h:37:0,
from /opt/Qt/5.5/gcc_64/include/QtCore/QSet:1,
from /src/wmathtest/Tag.h:5,
from /src/wmathtest/Exercise.h:5,
from /src/wmathtest/Exercise.cpp:1:
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:65:52: note: constexpr uint qHash(char, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(char key, uint seed = 0) Q_DECL_NOTHROW { return uint(key) ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:65:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘char’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:66:52: note: constexpr uint qHash(uchar, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(uchar key, uint seed = 0) Q_DECL_NOTHROW { return uint(key) ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:66:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘uchar {aka unsigned char}’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:67:52: note: constexpr uint qHash(signed char, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(signed char key, uint seed = 0) Q_DECL_NOTHROW { return uint(key) ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:67:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘signed char’
In file included from /opt/Qt/5.5/gcc_64/include/QtCore/qset.h:37:0,
from /opt/Qt/5.5/gcc_64/include/QtCore/QSet:1,
from /src/wmathtest/Tag.h:5,
from /src/wmathtest/Exercise.h:5,
from /src/wmathtest/Exercise.cpp:1:
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:68:52: note: constexpr uint qHash(ushort, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(ushort key, uint seed = 0) Q_DECL_NOTHROW { return uint(key) ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:68:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘ushort {aka short unsigned int}’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:69:52: note: constexpr uint qHash(short int, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(short key, uint seed = 0) Q_DECL_NOTHROW { return uint(key) ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:69:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘short int’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:70:52: note: constexpr uint qHash(uint, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(uint key, uint seed = 0) Q_DECL_NOTHROW { return key ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:70:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘uint {aka unsigned int}’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:71:52: note: constexpr uint qHash(int, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(int key, uint seed = 0) Q_DECL_NOTHROW { return uint(key) ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:71:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘int’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:72:52: note: constexpr uint qHash(ulong, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(ulong key, uint seed = 0) Q_DECL_NOTHROW
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:72:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘ulong {aka long unsigned int}’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:78:52: note: constexpr uint qHash(long int, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(long key, uint seed = 0) Q_DECL_NOTHROW { return qHash(ulong(key), seed); }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:78:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘long int’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:79:52: note: constexpr uint qHash(quint64, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(quint64 key, uint seed = 0) Q_DECL_NOTHROW
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:79:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘quint64 {aka long long unsigned int}’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:83:52: note: constexpr uint qHash(qint64, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(qint64 key, uint seed = 0) Q_DECL_NOTHROW { return qHash(quint64(key), seed); }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:83:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘qint64 {aka long long int}’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:84:42: note: uint qHash(float, uint)
Q_CORE_EXPORT Q_DECL_CONST_FUNCTION uint qHash(float key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:84:42: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘float’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:85:42: note: uint qHash(double, uint)
Q_CORE_EXPORT Q_DECL_CONST_FUNCTION uint qHash(double key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:85:42: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘double’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:87:42: note: uint qHash(long double, uint)
Q_CORE_EXPORT Q_DECL_CONST_FUNCTION uint qHash(long double key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:87:42: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘long double’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:89:52: note: constexpr uint qHash(QChar, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(const QChar key, uint seed = 0) Q_DECL_NOTHROW { return qHash(key.unicode(), seed); }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:89:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘QChar’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:90:41: note: uint qHash(const QByteArray&, uint)
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION uint qHash(const QByteArray &key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:90:41: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘const QByteArray&’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:91:41: note: uint qHash(const QString&, uint)
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION uint qHash(const QString &key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:91:41: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘const QString&’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:92:41: note: uint qHash(const QStringRef&, uint)
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION uint qHash(const QStringRef &key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:92:41: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘const QStringRef&’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:93:41: note: uint qHash(const QBitArray&, uint)
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION uint qHash(const QBitArray &key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:93:41: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘const QBitArray&’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:94:41: note: uint qHash(QLatin1String, uint)
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION uint qHash(QLatin1String key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:94:41: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘QLatin1String’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:98:32: note: template<class T> uint qHash(const T*, uint)
template <class T> inline uint qHash(const T *key, uint seed = 0) Q_DECL_NOTHROW
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:98:32: note: template argument deduction/substitution failed:
In file included from /opt/Qt/5.5/gcc_64/include/QtCore/qglobal.h:74:0,
from /opt/Qt/5.5/gcc_64/include/QtCore/qchar.h:37,
from /opt/Qt/5.5/gcc_64/include/QtCore/qstring.h:41,
from /opt/Qt/5.5/gcc_64/include/QtCore/QString:1,
from /src/wmathtest/LaTeXText.h:4,
from /src/wmathtest/Exercise.h:4,
from /src/wmathtest/Exercise.cpp:1:
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:103:5: note: mismatched types ‘const T*’ and ‘WMathTest::Tag’
Q_DECL_NOEXCEPT_EXPR(noexcept(qHash(t)))
^
src/wmathtest/CMakeFiles/wmathtest.dir/build.make:146: recipe for target 'src/wmathtest/CMakeFiles/wmathtest.dir/Exercise.cpp.o' failed
make[2]: *** [src/wmathtest/CMakeFiles/wmathtest.dir/Exercise.cpp.o] Error 1
CMakeFiles/Makefile2:160: recipe for target 'src/wmathtest/CMakeFiles/wmathtest.dir/all' failed
make[1]: *** [src/wmathtest/CMakeFiles/wmathtest.dir/all] Error 2
Makefile:76: recipe for target 'all' failed
Exercise.cpp.o
In file included from /opt/Qt/5.5/gcc_64/include/QtCore/qglobal.h:74:0,
from /opt/Qt/5.5/gcc_64/include/QtCore/qchar.h:37,
from /opt/Qt/5.5/gcc_64/include/QtCore/qstring.h:41,
from /opt/Qt/5.5/gcc_64/include/QtCore/QString:1,
from /wmathtest/LaTeXText.h:4,
from /src/wmathtest/Exercise.h:4,
from /wmathtest/Exercise.cpp:1:
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h: In instantiation of ‘uint qHash(const T&, uint) [with T = WMathTest::Tag; uint = unsigned int]’:
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:952:32: required from ‘QHash<Key, T>::Node** QHash<Key, T>::findNode(const Key&, uint*) const [with Key = WMathTest::Tag; T = QHashDummyValue; QHash<Key, T>::Node = QHashNode<WMathTest::Tag, QHashDummyValue>; uint = unsigned int]’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:808:36: required from ‘QHash<Key, T>::iterator QHash<Key, T>::insert(const Key&, const T&) [with Key = WMathTest::Tag; T = QHashDummyValue]’
/opt/Qt/5.5/gcc_64/include/QtCore/qset.h:188:94: required from ‘QSet<T>::iterator QSet<T>::insert(const T&) [with T = WMathTest::Tag]’
/wmathtest/Exercise.cpp:22:22: required from here
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:103:5: error: no matching function for call to ‘qHash(const WMathTest::Tag&)’
Q_DECL_NOEXCEPT_EXPR(noexcept(qHash(t)))
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:103:5: note: candidates are:
In file included from /opt/Qt/5.5/gcc_64/include/QtCore/qset.h:37:0,
from /opt/Qt/5.5/gcc_64/include/QtCore/QSet:1,
from /wmathtest/Tag.h:5,
from /wmathtest/Exercise.h:5,
from /wmathtest/Exercise.cpp:1:
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:65:52: note: constexpr uint qHash(char, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(char key, uint seed = 0) Q_DECL_NOTHROW { return uint(key) ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:65:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘char’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:66:52: note: constexpr uint qHash(uchar, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(uchar key, uint seed = 0) Q_DECL_NOTHROW { return uint(key) ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:66:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘uchar {aka unsigned char}’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:67:52: note: constexpr uint qHash(signed char, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(signed char key, uint seed = 0) Q_DECL_NOTHROW { return uint(key) ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:67:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘signed char’
In file included from /opt/Qt/5.5/gcc_64/include/QtCore/qset.h:37:0,
from /opt/Qt/5.5/gcc_64/include/QtCore/QSet:1,
from /home/daniele/projects/wmathtestgenerator/src/wmathtest/Tag.h:5,
from /Exercise.h:5,
from /wmathtest/Exercise.cpp:1:
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:68:52: note: constexpr uint qHash(ushort, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(ushort key, uint seed = 0) Q_DECL_NOTHROW { return uint(key) ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:68:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘ushort {aka short unsigned int}’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:69:52: note: constexpr uint qHash(short int, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(short key, uint seed = 0) Q_DECL_NOTHROW { return uint(key) ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:69:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘short int’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:70:52: note: constexpr uint qHash(uint, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(uint key, uint seed = 0) Q_DECL_NOTHROW { return key ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:70:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘uint {aka unsigned int}’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:71:52: note: constexpr uint qHash(int, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(int key, uint seed = 0) Q_DECL_NOTHROW { return uint(key) ^ seed; }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:71:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘int’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:72:52: note: constexpr uint qHash(ulong, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(ulong key, uint seed = 0) Q_DECL_NOTHROW
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:72:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘ulong {aka long unsigned int}’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:78:52: note: constexpr uint qHash(long int, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(long key, uint seed = 0) Q_DECL_NOTHROW { return qHash(ulong(key), seed); }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:78:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘long int’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:79:52: note: constexpr uint qHash(quint64, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(quint64 key, uint seed = 0) Q_DECL_NOTHROW
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:79:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘quint64 {aka long long unsigned int}’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:83:52: note: constexpr uint qHash(qint64, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(qint64 key, uint seed = 0) Q_DECL_NOTHROW { return qHash(quint64(key), seed); }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:83:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘qint64 {aka long long int}’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:84:42: note: uint qHash(float, uint)
Q_CORE_EXPORT Q_DECL_CONST_FUNCTION uint qHash(float key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:84:42: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘float’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:85:42: note: uint qHash(double, uint)
Q_CORE_EXPORT Q_DECL_CONST_FUNCTION uint qHash(double key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:85:42: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘double’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:87:42: note: uint qHash(long double, uint)
Q_CORE_EXPORT Q_DECL_CONST_FUNCTION uint qHash(long double key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:87:42: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘long double’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:89:52: note: constexpr uint qHash(QChar, uint)
Q_DECL_CONST_FUNCTION Q_DECL_CONSTEXPR inline uint qHash(const QChar key, uint seed = 0) Q_DECL_NOTHROW { return qHash(key.unicode(), seed); }
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:89:52: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘QChar’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:90:41: note: uint qHash(const QByteArray&, uint)
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION uint qHash(const QByteArray &key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:90:41: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘const QByteArray&’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:91:41: note: uint qHash(const QString&, uint)
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION uint qHash(const QString &key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:91:41: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘const QString&’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:92:41: note: uint qHash(const QStringRef&, uint)
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION uint qHash(const QStringRef &key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:92:41: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘const QStringRef&’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:93:41: note: uint qHash(const QBitArray&, uint)
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION uint qHash(const QBitArray &key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:93:41: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘const QBitArray&’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:94:41: note: uint qHash(QLatin1String, uint)
Q_CORE_EXPORT Q_DECL_PURE_FUNCTION uint qHash(QLatin1String key, uint seed = 0) Q_DECL_NOTHROW;
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:94:41: note: no known conversion for argument 1 from ‘const WMathTest::Tag’ to ‘QLatin1String’
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:98:32: note: template<class T> uint qHash(const T*, uint)
template <class T> inline uint qHash(const T *key, uint seed = 0) Q_DECL_NOTHROW
^
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:98:32: note: template argument deduction/substitution failed:
In file included from /opt/Qt/5.5/gcc_64/include/QtCore/qglobal.h:74:0,
from /opt/Qt/5.5/gcc_64/include/QtCore/qchar.h:37,
from /opt/Qt/5.5/gcc_64/include/QtCore/qstring.h:41,
from /opt/Qt/5.5/gcc_64/include/QtCore/QString:1,
from /home/daniele/projects/wmathtestgenerator/src/wmathtest/LaTeXText.h:4,
from /home/daniele/projects/wmathtestgenerator/src/wmathtest/Exercise.h:4,
from /thtest/Exercise.cpp:1:
/opt/Qt/5.5/gcc_64/include/QtCore/qhash.h:103:5: note: mismatched types ‘const T*’ and ‘WMathTest::Tag’
Q_DECL_NOEXCEPT_EXPR(noexcept(qHash(t)))
^
src/wmathtest/CMakeFiles/wmathtest.dir/build.make:146: recipe for target 'src/wmathtest/CMakeFiles/wmathtest.dir/Exercise.cpp.o' failed
make[2]: *** [src/wmathtest/CMakeFiles/wmathtest.dir/Exercise.cpp.o] Error 1
CMakeFiles/Makefile2:160: recipe for target 'src/wmathtest/CMakeFiles/wmathtest.dir/all' failed
make[1]: *** [src/wmathtest/CMakeFiles/wmathtest.dir/all] Error 2
Makefile:76: recipe for target 'all' failed
Я создал класс, operator== и qHash для класса. Тогда я создал typedef для класса, но это не работает.
Что я делаю не так?
Tag.h
#ifndef WMATHTEST_TAG_H_
#define WMATHTEST_TAG_H_
#include <QString>
#include <QSet>
namespace WMathTest {
class Tag {
public:
Tag() = default;
Tag(const QString &text);
Tag(const Tag &tag) = default;
virtual ~Tag() = default;
void setText(const QString &text);
const QString& getText() const;
bool operator==(const Tag &other);
private:
QString m_text;
};
} // namespace WMathTestinline uint qHash(const WMathTest::Tag &tag, uint seed) {
return qHash(tag.getText(), seed);
}
typedef QSet<WMathTest::Tag> TagList;
#endif // !WMATHTEST_TAG_H_
Tag.cpp
#include "wmathtest/Tag.h"
namespace WMathTest {
///////////////////////////////////////////////////////////////////////////////
// PUBLIC SECTION //
///////////////////////////////////////////////////////////////////////////////
Tag::Tag(const QString &text) :
m_text(text) {
}
void Tag::setText(const QString &text) {
m_text = text;
}
const QString& Tag::getText() const {
return m_text;
}
bool Tag::operator==(const Tag &other) {
return m_text == other.m_text;
}
} // namespace WMathTest
Exercise.h
#ifndef WMATHTEST_EXERCISE_H_
#define WMATHTEST_EXERCISE_H_
#include "wmathtest/LaTeXText.h"#include "wmathtest/Tag.h"#include <QString>
namespace WMathTest {
class Exercise {
public:
Exercise() = default;
virtual ~Exercise() = default;
void setID(const QString &id);
void setProblem(const LaTeXText &problem);
void setSolution(const LaTeXText &solution);
void addArgumentTag(const Tag &tag);
void addArgumentTag(const QString &tag);
QString getID() const;
LaTeXText getProblem() const;
LaTeXText getSolution() const;
const TagList& getArgumentTagList() const;
private:
QString m_id;
LaTeXText m_problem;
LaTeXText m_solution;
TagList m_tagList;
};
} // namespace WMathTest
#endif // !WMATHTEST_EXERCISE_H_
Exercise.cpp
#include "wmathtest/Exercise.h"
namespace WMathTest {
///////////////////////////////////////////////////////////////////////////////
// PUBLIC SECTION //
///////////////////////////////////////////////////////////////////////////////
void Exercise::setID(const QString &id) {
m_id = id;
}
void Exercise::setProblem(const LaTeXText &problem) {
m_problem = problem;
}
void Exercise::setSolution(const LaTeXText &solution) {
m_solution = solution;
}
void Exercise::addArgumentTag(const Tag &tag) {
m_tagList.insert(tag);
}
void Exercise::addArgumentTag(const QString &tag) {
m_tagList.insert(Tag(tag));
}
QString Exercise::getID() const {
return m_id;
}
LaTeXText Exercise::getProblem() const {
return m_problem;
}
LaTeXText Exercise::getSolution() const {
return m_solution;
}
const TagList& Exercise::getArgumentTagList() const {
return m_tagList;
}
} // namespace WMathTest
Решение
Хеш — это унарная функция (только один аргумент), и это функция в математическом смысле (возвращает то же значение для конкретного аргумента и возвращает действительное значение для полного набора аргументов).
Хэш-функция имеет одно важное условие, которое всегда должно выполняться для правильной работы: если два объекта считаются равными, то значения хеш-функции для этих объектов ДОЛЖНЫ быть также равными. Так, например, если вы в каком контейнере нечувствительны к регистру, где строки являются ключом, вы должны предоставить хеш-функцию без учета регистра.
Обратите внимание, что дополнительный аргумент для qHash-функции, которые вы видите в документации: seed всегда имеет значение по умолчанию! Так что эта функция может быть вызвана с одним аргументом! Этот аргумент является просто опцией, которая дает вам возможность настроить хеш-функцию при создании пользовательской хеш-функции для сложного типа.
Исправьте ваш код следующим образом:
inline uint qHash(const WMathTest::Tag &tag) {
return qHash(tag.getText(), 0xa03f); // arbitrary value
}
или вот так:
inline uint qHash(const WMathTest::Tag &tag, uint seed = 0) {
return qHash(tag.getText(), seed^0xa03f);
}
В случае более сложного типа хеш-функция может выглядеть следующим образом (пример, почему seed может быть полезен):
inline uint qHash(const DoubleStringValue &tag, uint seed = 0) {
return qHash(tag.firstText(), seed^0xa03f)^qHash(tag.secondText(), seed^0x17a317a3);
}
Обратите внимание, что таким образом, если есть два DoubleStringValue объекты, где firstText а также secondText перевернутые значения хеш-функции для них обоих будут разными.
Я рекомендую прочитать некоторую документацию о том, как работают контейнеры с хэш-функциями и почему они работают быстрее, чем альтернативные решения (например, красно-черное дерево).
Другие решения
Я нашел решение сам. Очевидно, это была моя ошибка, но она не связана с моей реализацией qHash.
Я сделал ошибку в operator== объявление:
bool operator==(const Tag &other);
Декларация пропускает const Классификатор. Так должно быть
bool operator==(const Tag &other) const;