std::strstreambuf (3) - Linux Manuals

std::strstreambuf: std::strstreambuf

NAME

std::strstreambuf - std::strstreambuf

Synopsis

Defined in header <strstream>
class strstreambuf : public std::basic_streambuf<char> (deprecated in C++98)

std::strstreambuf is a std::basic_streambuf whose associated character sequence is a character array, which may be constant (e.g. a string literal), modifyable but not dynamic (e.g. a stack-allocated array), or dynamic, in which case the std::strstreambuf may be allowed to reallocate the array as necessary to accomodate output (e.g. by calling delete[] and new[] or user-provided functions).
Typical implementation of a std::strstreambuf holds four private data members:
1) buffer state, a bitmask type which can represent any combination of the four values "allocated" (destructor will deallocate), "constant" (output not allowed), "dynamic" (output may reallocate), or "frozen" (deallocation and reallocation are not allowed)
2) allocated buffer size (the beginning of the buffer does not need a special data member, it may be stored in the inherited pointer eback())
3) pointer to user-provided allocation function
4) pointer to user-provided deallocation function.

Notes

After any call to str() on a stream with a dynamic buffer, a call to freeze(false) is required to allow the strstreambuf destructor to deallocate the buffer when necessary.

Member functions

Public member functions

              constructs a strstreambuf object
constructor (public member function)

destructor destructs a strstreambuf object, optionally deallocating the character array
              (virtual public member function)
[virtual]
              sets/clears the frozen state of the buffer
freeze (public member function)
              marks the buffer frozen and returns the beginning pointer of the input sequence
str (public member function)
              returns the next pointer minus the beginning pointer in the output sequence: the number of characters written
pcount (public member function)

Protected member functions

underflow reads a character from the input sequence without advancing the next pointer
              (virtual protected member function)
[virtual]

pbackfail backs out the input sequence to unget a character
              (virtual protected member function)
[virtual]

overflow appends a character to the output sequence, may reallocate or initially allocate the buffer if dynamic and not frozen
              (virtual protected member function)
[virtual]

setbuf attempts to replace the controlled character sequence with an array
              (virtual protected member function)
[virtual]

seekoff repositions the next pointer in the input sequence, output sequence, or both, using relative addressing
              (virtual protected member function)
[virtual]

seekpos repositions the next pointer in the input sequence, output sequence, or both using absolute addressing
              (virtual protected member function)
[virtual]

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

destructor destructs the basic_streambuf object
                      (virtual public member function of std::basic_streambuf<CharT,Traits>)
[virtual]

Locales

                      invokes imbue()
pubimbue (public member function of std::basic_streambuf<CharT,Traits>)
                      obtains a copy of the associated locale
getloc (public member function of std::basic_streambuf<CharT,Traits>)

Positioning

                      invokes setbuf()
pubsetbuf (public member function of std::basic_streambuf<CharT,Traits>)
                      invokes seekoff()
pubseekoff (public member function of std::basic_streambuf<CharT,Traits>)
                      invokes seekpos()
pubseekpos (public member function of std::basic_streambuf<CharT,Traits>)
                      invokes sync()
pubsync (public member function of std::basic_streambuf<CharT,Traits>)

Get area

                      obtains the number of characters immediately available in the get area
in_avail (public member function of std::basic_streambuf<CharT,Traits>)
                      advances the input sequence, then reads one character without advancing again
snextc (public member function of std::basic_streambuf<CharT,Traits>)
                      reads one character from the input sequence and advances the sequence
sbumpc (public member function of std::basic_streambuf<CharT,Traits>)

stossc advances the input sequence as if by calling sbumpc() and discarding the result
                      (public member function)
(deprecated in C++98)
(removed in C++17)
                      reads one character from the input sequence without advancing the sequence
sgetc (public member function of std::basic_streambuf<CharT,Traits>)
                      invokes xsgetn()
sgetn (public member function of std::basic_streambuf<CharT,Traits>)

Put area

                      writes one character to the put area and advances the next pointer
sputc (public member function of std::basic_streambuf<CharT,Traits>)
                      invokes xsputn()
sputn (public member function of std::basic_streambuf<CharT,Traits>)

Putback

                      puts one character back in the input sequence
sputbackc (public member function of std::basic_streambuf<CharT,Traits>)
                      moves the next pointer in the input sequence back by one
sungetc (public member function of std::basic_streambuf<CharT,Traits>)

Protected member functions

              constructs a basic_streambuf object
constructor (protected member function)

operator= replaces a basic_streambuf object
              (protected member function)
(C++11)

swap swaps two basic_streambuf objects
              (protected member function)
(C++11)

Locales

imbue changes the associated locale
              (virtual protected member function of std::basic_streambuf<CharT,Traits>)
[virtual]

Positioning

setbuf replaces the buffer with user-defined array, if permitted
              (virtual protected member function of std::basic_streambuf<CharT,Traits>)
[virtual]

seekoff 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]

seekpos 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]

sync synchronizes the buffers with the associated character sequence
              (virtual protected member function of std::basic_streambuf<CharT,Traits>)
[virtual]

Get area

showmanyc 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]

underflow reads characters from the associated input sequence to the get area
              (virtual protected member function of std::basic_streambuf<CharT,Traits>)
[virtual]

uflow 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]

xsgetn reads multiple characters from the input sequence
              (virtual protected member function of std::basic_streambuf<CharT,Traits>)
[virtual]

eback returns a pointer to the beginning, current character and the end of the get area
gptr (protected member function)
egptr
              advances the next pointer in the input sequence
gbump (protected member function)
              repositions the beginning, next, and end pointers of the input sequence
setg (protected member function)

Put area

xsputn writes multiple characters to the output sequence
              (virtual protected member function of std::basic_streambuf<CharT,Traits>)
[virtual]

overflow writes characters to the associated output sequence from the put area
              (virtual protected member function of std::basic_streambuf<CharT,Traits>)
[virtual]

pbase returns a pointer to the beginning, current character and the end of the put area
pptr (protected member function)
epptr
              advances the next pointer of the output sequence
pbump (protected member function)
              repositions the beginning, next, and end pointers of the output sequence
setp (protected member function)

Putback

pbackfail puts a character back into the input sequence, possibly modifying the input sequence
              (virtual protected member function of std::basic_streambuf<CharT,Traits>)
[virtual]