Qt::partial_ordering Class | Qt Core (original) (raw)
class Qt::partial_ordering
Qt::partial_ordering represents the result of a comparison that allows for unordered results. More...
| Header: | #include |
|---|---|
| CMake: | find_package(Qt6 REQUIRED COMPONENTS Core) target_link_libraries(mytarget PRIVATE Qt6::Core) |
| qmake: | QT += core |
| Since: | Qt 6.7 |
Public Functions
Static Public Members
| bool | is_eq(Qt::partial_ordering o) |
|---|---|
| bool | is_gt(Qt::partial_ordering o) |
| bool | is_gteq(Qt::partial_ordering o) |
| bool | is_lt(Qt::partial_ordering o) |
| bool | is_lteq(Qt::partial_ordering o) |
| bool | is_neq(Qt::partial_ordering o) |
| bool | operator!=(Qt::partial_ordering lhs, Qt::partial_ordering rhs) |
| bool | operator==(Qt::partial_ordering lhs, Qt::partial_ordering rhs) |
Detailed Description
A value of type Qt::partial_ordering is typically returned from a three-way comparison function. Such a function compares two objects, establishing whether they are ordered and, if so, their ordering. It uses this return type to indicate that the ordering is partial; that is, not all pairs of values are ordered.
Qt::partial_ordering has four values, represented by the following symbolic constants:
- less represents that the left operand is less than the right;
- equivalent represents that the two operands are equivalent;
- greater represents that the left operand is greater than the right;
- unordered represents that the two operands are not ordered.
Qt::partial_ordering is idiomatically used by comparing an instance against a literal zero, for instance like this:
// given a, b, c, d as objects of some type that allows for a 3-way compare, // and a compare function declared as follows:
Qt::partial_ordering compare(T lhs, T rhs); // defined out-of-line
~~~
Qt::partial_ordering result = compare(a, b); if (result < 0) { // a is less than b }
if (compare(c, d) >= 0) { // c is greater than or equal to d }
Comparing Qt::partial_ordering::unordered against literal 0 always returns a false result.
See also Qt::strong_ordering, Qt::weak_ordering, and Comparison types overview.
Member Function Documentation
[constexpr noexcept] partial_ordering::partial_ordering(std::partial_ordering stdorder)
Constructs a Qt::partial_ordering object from stdorder using the following rules:
- std::partial_ordering::less converts to less.
- std::partial_ordering::equivalent converts to equivalent.
- std::partial_ordering::greater converts to greater.
- std::partial_ordering::unordered converts to unordered
[constexpr noexcept] std::partial_ordering partial_ordering::operator std::partial_ordering() const
Converts this Qt::partial_ordering value to a std::partial_ordering object using the following rules:
- less converts to std::partial_ordering::less.
- equivalent converts to std::partial_ordering::equivalent.
- greater converts to std::partial_ordering::greater.
- unordered converts to std::partial_ordering::unordered.
Member Variable Documentation
const Qt::partial_ordering partial_ordering::equivalent
Represents the result of a comparison where the two operands are equivalent.
const Qt::partial_ordering partial_ordering::greater
Represents the result of a comparison where the left operand is greater than the right operand.
const Qt::partial_ordering partial_ordering::less
Represents the result of a comparison where the left operand is less than the right operand.
const Qt::partial_ordering partial_ordering::unordered
Represents the result of a comparison where there is no ordering relationship between the two operands.
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