std:: basic_spanbuf
|
Defined in header
<spanstream>
|
||
|
template
<
class
CharT,
|
(since C++23) | |
std::basic_spanbuf
is a
std::basic_streambuf
whose associated character sequence is a memory-resident sequence of arbitrary characters, which can be initialized from or made available as an instance of
std::
span
<
CharT
>
.
std::basic_spanbuf
performs I/O on a fixed buffer, and therefore it does not attempt to obtain a new buffer when the underlying buffer is exhausted.
Several typedefs for common character types are provided:
|
Defined in header
<spanstream>
|
|
| Type | Definition |
std::spanbuf
|
std :: basic_spanbuf < char > |
std::wspanbuf
|
std :: basic_spanbuf < wchar_t > |
Member types
| Member type | Definition |
char_type
|
CharT
|
traits_type
|
Traits
; the program is ill-formed if
Traits::char_type
is not
CharT
.
|
int_type
|
Traits::int_type
|
pos_type
|
Traits::pos_type
|
off_type
|
Traits::off_type
|
Data members
| Member name | Definition |
mod
(private)
|
A
std::ios_base::openmode
recording the open mode.
( exposition-only member object* ) |
buf
(private)
|
A
std::
span
<
CharT
>
referencing the underlying buffer.
( exposition-only member object* ) |
Member functions
Public member functions |
|
constructs a
basic_spanbuf
object
(public member function) |
|
|
(destructor)
[virtual]
|
destroys the
basic_spanbuf
object
(virtual public member function) |
assigns a
basic_spanbuf
object
(public member function) |
|
swaps two
basic_spanbuf
objects
(public member function) |
|
|
obtains or initializes an underlying buffer according to mode
(public member function) |
|
Protected member functions |
|
|
[virtual]
|
attempts to replace the controlled character sequence with an array
(virtual protected member function) |
|
[virtual]
|
repositions the next pointer in the input sequence, output sequence, or both, using relative addressing
(virtual protected member function) |
|
[virtual]
|
repositions the next pointer in the input sequence, output sequence, or both using absolute addressing
(virtual protected member function) |
Non-member functions
|
(C++23)
|
specializes the
std::swap
algorithm
(function template) |
Inherited from std:: basic_streambuf
Member types
| Member type | Definition |
char_type
|
CharT
|
traits_type
|
Traits
; the program is ill-formed if
Traits::char_type
is not
CharT
.
|
int_type
|
Traits::int_type
|
pos_type
|
Traits::pos_type
|
off_type
|
Traits::off_type
|
Member functions
|
[virtual]
|
destructs the
basic_streambuf
object
(virtual public member function of
std::basic_streambuf<CharT,Traits>
)
|
Locales |
|
|
invokes
imbue
(
)
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
|
obtains a copy of the associated locale
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
Positioning |
|
|
invokes
setbuf
(
)
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
|
invokes
seekoff
(
)
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
|
invokes
seekpos
(
)
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
|
invokes
sync
(
)
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
Get area |
|
|
obtains the number of characters immediately available in the get area
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
|
advances the input sequence, then reads one character without advancing again
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
|
(removed in C++17)
|
reads one character from the input sequence and advances the sequence
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
reads one character from the input sequence without advancing the sequence
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
|
invokes
xsgetn
(
)
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
Put area |
|
|
writes one character to the put area and advances the next pointer
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
|
invokes
xsputn
(
)
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
Putback |
|
|
puts one character back in the input sequence
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
|
moves the next pointer in the input sequence back by one
(public member function of
std::basic_streambuf<CharT,Traits>
)
|
|
Protected member functions
constructs a
basic_streambuf
object
(protected member function) |
|
|
(C++11)
|
replaces a
basic_streambuf
object
(protected member function) |
|
(C++11)
|
swaps two
basic_streambuf
objects
(protected member function) |
Locales |
|
|
[virtual]
|
changes the associated locale
(virtual protected member function of
std::basic_streambuf<CharT,Traits>
)
|
Positioning |
|
|
[virtual]
|
replaces the buffer with user-defined array, if permitted
(virtual protected member function of
std::basic_streambuf<CharT,Traits>
)
|
|
[virtual]
|
repositions the next pointer in the input sequence, output sequence, or both, using relative addressing
(virtual protected member function of
std::basic_streambuf<CharT,Traits>
)
|
|
[virtual]
|
repositions the next pointer in the input sequence, output sequence, or both using absolute addressing
(virtual protected member function of
std::basic_streambuf<CharT,Traits>
)
|
|
[virtual]
|
synchronizes the buffers with the associated character sequence
(virtual protected member function of
std::basic_streambuf<CharT,Traits>
)
|
Get area |
|
|
[virtual]
|
obtains the number of characters available for input in the associated input sequence, if known
(virtual protected member function of
std::basic_streambuf<CharT,Traits>
)
|
|
[virtual]
|
reads characters from the associated input sequence to the get area
(virtual protected member function of
std::basic_streambuf<CharT,Traits>
)
|
|
[virtual]
|
reads characters from the associated input sequence to the get area and advances the next pointer
(virtual protected member function of
std::basic_streambuf<CharT,Traits>
)
|
|
[virtual]
|
reads multiple characters from the input sequence
(virtual protected member function of
std::basic_streambuf<CharT,Traits>
)
|
|
returns a pointer to the beginning, current character and the end of the get area
(protected member function) |
|
|
advances the next pointer in the input sequence
(protected member function) |
|
|
repositions the beginning, next, and end pointers of the input sequence
(protected member function) |
|
Put area |
|
|
[virtual]
|
writes multiple characters to the output sequence
(virtual protected member function of
std::basic_streambuf<CharT,Traits>
)
|
|
[virtual]
|
writes characters to the associated output sequence from the put area
(virtual protected member function of
std::basic_streambuf<CharT,Traits>
)
|
|
returns a pointer to the beginning, current character and the end of the put area
(protected member function) |
|
|
advances the next pointer of the output sequence
(protected member function) |
|
|
repositions the beginning, next, and end pointers of the output sequence
(protected member function) |
|
Putback |
|
|
[virtual]
|
puts a character back into the input sequence, possibly modifying the input sequence
(virtual protected member function of
std::basic_streambuf<CharT,Traits>
)
|
Notes
std::basic_spanbuf
does not own the underlying buffer.
It is the responsibility of programmers to ensure the underlying buffer is in its lifetime when used by a
std::basic_spanbuf
object. Additional synchronization may be needed if more than one thread operates the same underlying buffer through different
std::basic_spanbuf
objects.
| Feature-test macro | Value | Std | Feature |
|---|---|---|---|
__cpp_lib_spanstream
|
202106L | (C++23) |
std::spanbuf
,
std::spanstream
|
See also
|
implements raw string device
(class template) |
|
|
(deprecated in C++98)
(removed in C++26)
|
implements raw character array device
(class) |