libpqxx
The C++ client library for PostgreSQL
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pqxx::nullness< std::string_view > Struct Reference

There's no real null for std::string_view. More...

Inheritance diagram for pqxx::nullness< std::string_view >:

Static Public Member Functions

static bool is_null (std::string_view const &value)
 Is value a null?
static std::string_view null ()
 Return a null value.
Static Public Member Functions inherited from pqxx::no_null< std::string_view >
static constexpr bool is_null (std::string_view const &) noexcept
 Does a given value correspond to an SQL null value?

Static Public Attributes

static bool has_null
 Does this type have a null value?
static bool always_null
 Is this type always null?
Static Public Attributes inherited from pqxx::no_null< std::string_view >
static constexpr bool has_null
 Does TYPE have a "built-in null value"?
static constexpr bool always_null
 Are all values of this type null?

Detailed Description

There's no real null for std::string_view.

I'm not sure how clear-cut this is: a string_view may have a null data pointer, which is analogous to a null char pointer.

Member Function Documentation

◆ null()

std::string_view pqxx::nullness< std::string_view, 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.


The documentation for this struct was generated from the following file:
  • /builddir/build/BUILD/libpqxx-7.10.1-build/libpqxx-7.10.1/redhat-linux-build/include/pqxx/internal/conversions.hxx