pqxx::nullness< std::optional< T > > Struct Template Reference

Static Public Member Functions
static constexpr bool	is_null (std::optional< T > const &v) noexcept
static constexpr std::optional< T >	null ()
static bool	is_null (std::optional< T > const &value)
	Is value a null?
static std::optional< T >	null ()
	Return a null value.

Static Public Attributes
static constexpr bool	has_null = true
static constexpr bool	always_null = nullness<T>::always_null
	Technically, you could have an optional of an always-null type.
static bool	has_null
	Does this type have a null value?
static bool	always_null
	Is this type always null?

Member Function Documentation

is_null() [1/2]

template<typename T>

static constexpr bool pqxx::nullness< std::optional< T > >::is_null ( std::optional< T > const & v )

inlinestaticconstexprnoexcept

is_null() [2/2]

static bool pqxx::nullness< std::optional< T >, void >::is_null ( std::optional< T > const & value )

static

Is value a null?

null() [1/2]

template<typename T>

static constexpr std::optional< T > pqxx::nullness< std::optional< T > >::null ( )

inlinestaticconstexpr

null() [2/2]

static std::optional< T > pqxx::nullness< std::optional< T >, void >::null ( )

staticnodiscard

Return a null value.

Don't use this in generic code to compare a value and see whether it is null. Some types may have multiple null values which do not compare as equal, or may define a null value which is not equal to anything including itself, like in SQL.

Member Data Documentation

always_null [1/2]

template<typename T>

bool pqxx::nullness< std::optional< T > >::always_null = nullness<T>::always_null

staticconstexpr

Technically, you could have an optional of an always-null type.

always_null [2/2]

bool pqxx::nullness< std::optional< T >, void >::always_null

static

Is this type always null?

has_null [1/2]

template<typename T>

bool pqxx::nullness< std::optional< T > >::has_null = true

staticconstexpr

has_null [2/2]

bool pqxx::nullness< std::optional< T >, void >::has_null

static

Does this type have a null value?

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The documentation for this struct was generated from the following file:

• /builddir/build/BUILD/libpqxx-7.10.5-build/libpqxx-7.10.5/redhat-linux-build/include/pqxx/internal/conversions.hxx