1+++ 2title = "`explicit operator bool() const noexcept`" 3description = "Returns true if a value is present. Constexpr, never throws." 4categories = ["observers"] 5weight = 590 6+++ 7 8Returns true if a value is present. Constexpr where possible. Alias for {{% api "bool has_value() const noexcept" %}}. 9 10*Requires*: Always available. 11 12*Complexity*: Constant time. 13 14*Guarantees*: Never throws an exception. 15