Marker-type wrapper: zero-terminated std::string_view. More...

Inheritance diagram for pqxx::zview:

Collaboration diagram for pqxx::zview:

Public Member Functions
constexpr	zview (char const text[], std::ptrdiff_t len) noexcept(noexcept(std::string_view{text, static_cast< std::size_t >(len)}))
	Convenience overload: construct using pointer and signed length.

constexpr	zview (char text[], std::ptrdiff_t len) noexcept(noexcept(std::string_view{text, static_cast< std::size_t >(len)}))
	Convenience overload: construct using pointer and signed length.

constexpr	zview (std::string_view other) noexcept
	Explicitly promote a `string_view` to a `zview`.

template<typename... Args>
constexpr	zview (Args &&...args)
	Construct from any initialiser you might use for `std::string_view`.

	zview (std::string const &str) noexcept

constexpr	zview (char const str[]) noexcept(noexcept(std::string_view{str}))
	Construct a `zview` from a C-style string.

template<size_t size>
constexpr	zview (char const (&literal)[size])
	Construct a `zview` from a string literal.

constexpr char const *	c_str () const &noexcept
	Either a null pointer, or a zero-terminated text buffer.

Detailed Description

Marker-type wrapper: zero-terminated std::string_view.

Warning: Use this only if the underlying string is zero-terminated.

When you construct a zview, you are promising that if the data pointer is non-null, the underlying string is zero-terminated. It otherwise behaves exactly like a std::string_view.

The terminating zero is not "in" the string, so it does not count as part of the view's length.

The added guarantee lets the view be used as a C-style string, which often matters since libpqxx builds on top of a C library. For this reason, zview also adds a c_str method.

Constructor & Destructor Documentation

◆ zview() [1/4]

template<typename... Args>

constexpr pqxx::zview::zview ( Args &&... args )

inlineexplicitconstexpr

Construct from any initialiser you might use for std::string_view.

Warning: Only do this if you are sure that the string is zero-terminated.

◆ zview() [2/4]

pqxx::zview::zview ( std::string const & str )

inlinenoexcept

Warning: There's an implicit conversion from std::string.

◆ zview() [3/4]

constexpr pqxx::zview::zview ( char const str[] )

inlineconstexprnoexcept

Construct a zview from a C-style string.

Warning: This scans the string to discover its length. So if you need to do it many times, it's probably better to create the zview once and re-use it.

◆ zview() [4/4]

template<size_t size>

constexpr pqxx::zview::zview ( char const (&) literal[size] )

inlineconstexpr

Construct a zview from a string literal.

A C++ string literal ("foo") normally looks a lot like a pointer to char const, but that's not really true. It's actually an array of char, which devolves to a pointer when you pass it.

For the purpose of creating a zview there is one big difference: if we know the array's size, we don't need to scan through the string in order to find out its length.

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