diff options
Diffstat (limited to 'src/corelib/tools')
-rw-r--r-- | src/corelib/tools/qmap.cpp | 4 | ||||
-rw-r--r-- | src/corelib/tools/qmap.h | 11 |
2 files changed, 7 insertions, 8 deletions
diff --git a/src/corelib/tools/qmap.cpp b/src/corelib/tools/qmap.cpp index 406eb31923..94ed47f898 100644 --- a/src/corelib/tools/qmap.cpp +++ b/src/corelib/tools/qmap.cpp @@ -399,7 +399,9 @@ void QMapDataBase::freeData(QMapDataBase *d) With QMap, the items are always sorted by key. \li The key type of a QHash must provide operator==() and a global qHash(Key) function. The key type of a QMap must provide - operator<() specifying a total order. + operator<() specifying a total order. Since Qt 5.8.1 it is also safe + to use a pointer type as key, even if the underlying operator<() + does not provide a total order. \endlist Here's an example QMap with QString keys and \c int values: diff --git a/src/corelib/tools/qmap.h b/src/corelib/tools/qmap.h index 96ce787446..3f4f034b4e 100644 --- a/src/corelib/tools/qmap.h +++ b/src/corelib/tools/qmap.h @@ -51,6 +51,7 @@ #include <map> #include <new> +#include <functional> #ifdef Q_COMPILER_INITIALIZER_LISTS #include <initializer_list> @@ -61,11 +62,8 @@ QT_BEGIN_NAMESPACE /* QMap uses qMapLessThanKey() to compare keys. The default implementation uses operator<(). For pointer types, - qMapLessThanKey() casts the pointers to integers before it - compares them, because operator<() is undefined on pointers - that come from different memory blocks. (In practice, this - is only a problem when running a program such as - BoundsChecker.) + qMapLessThanKey() uses std::less (because operator<() on + pointers can be used only between pointers in the same array). */ template <class Key> inline bool qMapLessThanKey(const Key &key1, const Key &key2) @@ -75,8 +73,7 @@ template <class Key> inline bool qMapLessThanKey(const Key &key1, const Key &key template <class Ptr> inline bool qMapLessThanKey(const Ptr *key1, const Ptr *key2) { - Q_STATIC_ASSERT(sizeof(quintptr) == sizeof(const Ptr *)); - return quintptr(key1) < quintptr(key2); + return std::less<const Ptr *>()(key1, key2); } struct QMapDataBase; |