May 5, 2017 · This is invalid. According to the rule of boolean conversions: A prvalue of type std:: nullptr_t , including nullptr , can be converted to a prvalue of type bool in context of direct-initialization. The resulting value is false. Quotes from the standard, §7.14/1 Boolean conversions [conv. bool ] For direct-initialization, a prvalue of type std :: nullptr_­t can be converted to a prvalue of type ...
Nov 2, 2015 · See this standard reference (bold emphasis mine): C++ 11 §4.12 Boolean conversions A prvalue of arithmetic, unscoped enumeration, pointer, or pointer to member type can be converted to a prvalue of type bool . A zero value, null pointer value, or null member pointer value is converted to false; any other value is converted to true. A prvalue of type std:: nullptr_t can be converted to a prvalue ...
Jul 22, 2022 · The nullptr feature together with nullptr_t is present in C++ since C++ 11 and has extensive implementation and application experience in that framework. This feature is also given under a different name in the Plan 9 C compiler, named nil.
Tip of the Week #141: Beware Implicit Conversions to - Abseil
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Jan 19, 2018 · Compare pointer types to nullptr (especially if the pointed-at type is implicitly convertible to bool ). Test container emptiness with boolean functions like std::optional< T >::has_value () (especially if the contained type is implicitly convertible to bool ).
Such expression e is said to be contextually implicitly converted to the specified type T . Note that explicit conversion functions are not considered, even though they are considered in contextual conversions to bool .(since C++ 11) the argument of the delete expression ( T is any object pointer type); integral constant expression, where a literal class is used ( T is any integral or unscoped ...
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https://cppreference.com/cpp/language/nullptr
The keyword nullptr denotes the pointer literal. It is a prvalue of type std:: nullptr_t . There exist implicit conversions from nullptr to null pointer value of any pointer type and any pointer to member type. Similar conversions exist for any null pointer constant, which includes values of type std:: nullptr_t as well as the macro NULL. Keywords ...
