std::basic_spanbuf<CharT,Traits>::basic_spanbuf

 

C++

Compiler support

Freestanding and hosted

Language

Standard library

Standard library headers

Named requirements

Feature test macros (C++20)

Language support library

Concepts library (C++20)

Metaprogramming library (C++11)

Diagnostics library

General utilities library

Strings library

Containers library

Iterators library

Ranges library (C++20)

Algorithms library

Numerics library

Localizations library

Input/output library

Filesystem library (C++17)

Regular expressions library (C++11)

Concurrency support library (C++11)

Execution support library (C++26)

Technical specifications

Symbols index

External libraries

 

Input/output library

I/O manipulators

Print functions (C++23)

C-style I/O

Buffers

basic_streambuf

basic_filebuf

basic_stringbuf

basic_spanbuf (C++23)

strstreambuf (C++98/26*)

basic_syncbuf (C++20)

Streams

Abstractions

ios_base

basic_ios

basic_istream

basic_ostream

basic_iostream

File I/O

basic_ifstream

basic_ofstream

basic_fstream

String I/O

basic_istringstream

basic_ostringstream

basic_stringstream

Array I/O

basic_ispanstream (C++23)

basic_ospanstream (C++23)

basic_spanstream (C++23)

istrstream (C++98/26*)

ostrstream (C++98/26*)

strstream (C++98/26*)

Synchronized Output

basic_osyncstream (C++20)

Types

streamoff

streamsize

fpos

Error category interface

iostream_category (C++11)

io_errc (C++11)

 

std::basic_spanbuf

Public member functions

basic_spanbuf::basic_spanbuf (C++23)

basic_spanbuf::operator= (C++23)

basic_spanbuf::swap (C++23)

basic_spanbuf::span (C++23)

Protected member functions

basic_spanbuf::setbuf (C++23)

basic_spanbuf::seekoff (C++23)

basic_spanbuf::seekpos (C++23)

Non-member functions

swap(std::basic_spanbuf) (C++23)

 

basic_spanbuf() : basic_spanbuf(std::ios_base::in | std::ios_base::out) {}	(1)	(since C++23)
explicit basic_spanbuf( std::ios_base::openmode which )     : basic_spanbuf(std::span<CharT>{}, which) {}	(2)	(since C++23)
explicit basic_spanbuf( std::span<CharT> buf, std::ios_base::openmode which =                             std::ios_base::in | std::ios_base::out );	(3)	(since C++23)
basic_spanbuf( const basic_spanbuf& ) = delete;	(4)	(since C++23)
basic_spanbuf( basic_spanbuf&& rhs );	(5)	(since C++23)

1) Default constructor. Creates a basic_spanbuf that has no underlying buffer and is opened for both input and output. The pointers to get and put area are set to the null pointer value.

2) Same as (1), except that the basic_spanbuf is opened in mode specified by which.

3) Creates a basic_spanbuf that manages the underlying buffer referenced by buf (or has no underlying buffer if buf is empty) and is opened in mode specified by which. The pointers to get and put area are set as following, or to the null pointer value if not mentioned in the table:

Set bits in open mode (affecting pointers to get area)	Return value after setting
	eback()	gptr()	egptr()
std::ios_base::in	s.data()	s.data()	s.data() + s.size()
Set bits in open mode (affecting pointers to put area)	Return value after setting
	pbase()	pptr()	epptr()
std::ios_base::out && !std::ios_base::ate	s.data()	s.data()	s.data() + s.size()
std::ios_base::out && std::ios_base::ate	s.data()	s.data() + s.size()	s.data() + s.size()

4) Copy constructor is deleted. basic_spanbuf is not copyable.

5) Move constructor. Move-constructs the std::basic_streambuf base subobject from that of rhs. The pointers to get and put area, the open mode, and the underlying buffer (if any) are identical to those in rhs before construction.
It is implementation-defined whether rhs still holds the underlying buffer after the move-construction.

Parameters

buf	-	a std::span referencing the underlying buffer
rhs	-	another basic_spanbuf
which	-	specifies stream open mode. It is bitmask type, the following constants are defined: Constant Explanation app seek to the end of stream before each write binary open in binary mode in open for reading out open for writing trunc discard the contents of the stream when opening ate seek to the end of stream immediately after open noreplace (C++23) open in exclusive mode

Notes

These constructors are typically called by the constructors of std::basic_ispanstream, std::basic_ospanstream, and std::basic_spanstream.

See also

(constructor)	constructs the basic_ispanstream (public member function of std::basic_ispanstream<CharT,Traits>)
(constructor)	constructs the basic_ospanstream (public member function of std::basic_ospanstream<CharT,Traits>)
(constructor)	constructs the basic_spanstream (public member function of std::basic_spanstream<CharT,Traits>)