Difference between revisions of "cpp/io/strstreambuf"

Latest revision as of 07:22, 6 April 2024

Defined in header `<strstream>`
class strstreambuf : public std::basic_streambuf<char>		(deprecated in C++98) (removed in C++26)

std::strstreambuf is a std::basic_streambuf whose associated character sequence is a character array, which may be constant (e.g. a string literal), modifiable 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 accommodate 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.

Public member functions
(constructor)	constructs a `strstreambuf` object (public member function) [edit]
(destructor) [virtual]	destructs a `strstreambuf` object, optionally deallocating the character array (virtual public member function) [edit]
freeze	sets/clears the frozen state of the buffer (public member function) [edit]
str	marks the buffer frozen and returns the beginning pointer of the input sequence (public member function) [edit]
pcount	returns the next pointer minus the beginning pointer in the output sequence: the number of characters written (public member function) [edit]
Protected member functions
underflow [virtual]	reads a character from the input sequence without advancing the next pointer (virtual protected member function) [edit]
pbackfail [virtual]	backs out the input sequence to unget a character (virtual protected member function) [edit]
overflow [virtual]	appends a character to the output sequence, may reallocate or initially allocate the buffer if dynamic and not frozen (virtual protected member function) [edit]
setbuf [virtual]	attempts to replace the controlled character sequence with an array (virtual protected member function) [edit]
seekoff [virtual]	repositions the next pointer in the input sequence, output sequence, or both, using relative addressing (virtual protected member function) [edit]
seekpos [virtual]	repositions the next pointer in the input sequence, output sequence, or both using absolute addressing (virtual protected member function) [edit]

Inherited from std::basic_streambuf

Member types

Member type	Definition
`char_type`	`CharT`[edit]
`traits_type`	`Traits`; the program is ill-formed if `Traits::char_type` is not `CharT`.[edit]
`int_type`	`Traits::int_type`[edit]
`pos_type`	`Traits::pos_type`[edit]
`off_type`	`Traits::off_type`[edit]

Member functions

(destructor) [virtual]	destructs the `basic_streambuf` object (virtual public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
Locales
pubimbue	invokes imbue() (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
getloc	obtains a copy of the associated locale (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
Positioning
pubsetbuf	invokes setbuf() (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
pubseekoff	invokes seekoff() (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
pubseekpos	invokes seekpos() (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
pubsync	invokes sync() (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
Get area
in_avail	obtains the number of characters immediately available in the get area (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
snextc	advances the input sequence, then reads one character without advancing again (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
sbumpcstossc (removed in C++17)	reads one character from the input sequence and advances the sequence (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
sgetc	reads one character from the input sequence without advancing the sequence (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
sgetn	invokes xsgetn() (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
Put area
sputc	writes one character to the put area and advances the next pointer (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
sputn	invokes xsputn() (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
Putback
sputbackc	puts one character back in the input sequence (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]
sungetc	moves the next pointer in the input sequence back by one (public member function of `std::basic_streambuf<CharT,Traits>`) [edit]

Protected member functions

(constructor)	constructs a `basic_streambuf` object (protected member function) [edit]
operator= (C++11)	replaces a `basic_streambuf` object (protected member function) [edit]
swap (C++11)	swaps two `basic_streambuf` objects (protected member function) [edit]
Locales
imbue [virtual]	changes the associated locale (virtual protected member function of `std::basic_streambuf<CharT,Traits>`) [edit]
Positioning
setbuf [virtual]	replaces the buffer with user-defined array, if permitted (virtual protected member function of `std::basic_streambuf<CharT,Traits>`) [edit]
seekoff [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>`) [edit]
seekpos [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>`) [edit]
sync [virtual]	synchronizes the buffers with the associated character sequence (virtual protected member function of `std::basic_streambuf<CharT,Traits>`) [edit]
Get area
showmanyc [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>`) [edit]
underflow [virtual]	reads characters from the associated input sequence to the get area (virtual protected member function of `std::basic_streambuf<CharT,Traits>`) [edit]
uflow [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>`) [edit]
xsgetn [virtual]	reads multiple characters from the input sequence (virtual protected member function of `std::basic_streambuf<CharT,Traits>`) [edit]
ebackgptregptr	returns a pointer to the beginning, current character and the end of the get area (protected member function) [edit]
gbump	advances the next pointer in the input sequence (protected member function) [edit]
setg	repositions the beginning, next, and end pointers of the input sequence (protected member function) [edit]
Put area
xsputn [virtual]	writes multiple characters to the output sequence (virtual protected member function of `std::basic_streambuf<CharT,Traits>`) [edit]
overflow [virtual]	writes characters to the associated output sequence from the put area (virtual protected member function of `std::basic_streambuf<CharT,Traits>`) [edit]
pbasepptrepptr	returns a pointer to the beginning, current character and the end of the put area (protected member function) [edit]
pbump	advances the next pointer of the output sequence (protected member function) [edit]
setp	repositions the beginning, next, and end pointers of the output sequence (protected member function) [edit]
Putback
pbackfail [virtual]	puts a character back into the input sequence, possibly modifying the input sequence (virtual protected member function of `std::basic_streambuf<CharT,Traits>`) [edit]

@@ Line 1: / Line 1: @@
-{{cpp/title|basic_stringbuf}}
+{{cpp/title|strstreambuf}}
-{{cpp/io/basic_stringbuf/sidebar}}
+{{cpp/io/strstreambuf/navbar}}
-{{ddcl | header=strstream | notes={{mark deprecated}} | 1=
+{{ddcl|header=strstream|deprecated=c++98|removed=c++26|1=
 class strstreambuf : public std::basic_streambuf<char>
 }}
-{{tt|std::strstreambuf}} is a specialization of {{cpp|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 {{tt|std::strstreambuf}} may be allowed to reallocate the array as necessary to accomodate output (e.g. by calling {{cpp|delete[]}} and {{cpp|new[]}} or user-provided functions).
+{{tt|std::strstreambuf}} is a {{lc|std::basic_streambuf}} whose associated character sequence is a character array, which may be constant (e.g. a string literal), modifiable but not dynamic (e.g. a stack-allocated array), or dynamic, in which case the {{tt|std::strstreambuf}} may be allowed to reallocate the array as necessary to accommodate output (e.g. by calling {{c/core|delete[]}} and {{c/core|new[]}} or user-provided functions).
 Typical implementation of a {{tt|std::strstreambuf}} holds four private data members:
-) 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" (output, deallocation, reallocation are not allowed)
+@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 {{lc|std::streambuf::eback|eback()}})
+@3@ pointer to user-provided allocation function
+@4@ pointer to user-provided deallocation function.
-) allocated buffer size
+===Notes===
+After any call to {{lc|str()}} on a stream with a dynamic buffer, a call to {{lc|freeze()|freeze(false)}} is required to allow the {{tt|strstreambuf}} destructor to deallocate the buffer when necessary.
-) pointer to user-provided allocation function
+{{tt|strstreambuf}} has been deprecated since C++98 and removed since C++26{{rev inl|since=c++23|. The recommended replacement is {{ltt|cpp/io/basic_spanbuf|std::spanbuf}}}}.
-) pointer to user-provided deallocation function.
 ===Member functions===
-{{dcl list begin}}
+{{dsc begin}}
-{{dcl list h1 | Public member functions}}
+{{dsc h1|Public member functions}}
-{{dcl list mem ctor | cpp/io/strstreambuf/strstreambuf | constructs a strstreambuf object}}
+{{dsc inc|cpp/io/strstreambuf/dsc strstreambuf}}
-{{dcl list mem vdtor | cpp/io/strstreambuf/~strstreambuf | destructs a strstreambuf object, optionally deallocating the character array}}
+{{dsc inc|cpp/io/strstreambuf/dsc ~strstreambuf}}
-{{dcl list mem fun | cpp/io/strstreambuf/freeze | marks the buffer frozen: the array object cannot not be altered, reallocated, or freed by the buffer}}
+{{dsc inc|cpp/io/strstreambuf/dsc freeze}}
-{{dcl list mem fun | cpp/io/strstreambuf/str | marks the buffer frozen and returns the beginning pointer of the input sequence}}
+{{dsc inc|cpp/io/strstreambuf/dsc str}}
-{{dcl list mem fun | cpp/io/strstreambuf/pcount | returns the next pointer minus the beginning pointer in the output sequence: the number of characters written }}
+{{dsc inc|cpp/io/strstreambuf/dsc pcount}}
-{{dcl list h1 | Protected member functions}}
+{{dsc h1|Protected member functions}}
-{{dcl list prot mem vfun | cpp/io/strstreambuf/underflow | reads a character from the input sequence without advancing the next pointer}}
+{{dsc inc|cpp/io/strstreambuf/dsc underflow}}
-{{dcl list prot mem vfun | cpp/io/strstreambuf/pbackfail | puts back a character into the input sequence }}
+{{dsc inc|cpp/io/strstreambuf/dsc pbackfail}}
-{{dcl list prot mem vfun | cpp/io/strstreambuf/overflow | appends a character to the output sequence, may reallocate or initially allocate the buffer if dynamic and not frozen}}
+{{dsc inc|cpp/io/strstreambuf/dsc overflow}}
-{{dcl list prot mem vfun | cpp/io/strstreambuf/setbuf | attempts to replace the controlled character sequence with an array }}
+{{dsc inc|cpp/io/strstreambuf/dsc setbuf}}
-{{dcl list prot mem vfun | cpp/io/strstreambuf/seekoff | repositions the next pointer in the input sequence, output sequence, or both, using relative addressing}}
+{{dsc inc|cpp/io/strstreambuf/dsc seekoff}}
-{{dcl list prot mem vfun | cpp/io/strstreambuf/seekpos | repositions the next pointer in the input sequence, output sequence, or both using absolute addressing}}
+{{dsc inc|cpp/io/strstreambuf/dsc seekpos}}
-{{dcl list end}}
+{{dsc end}}
 {{cpp/io/basic_streambuf/inherit}}
+{{langlinks|de|es|fr|it|ja|pt|ru|zh}}

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Print functions (C++23)
C-style I/O
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basic_streambuf
basic_filebuf
basic_stringbuf
basic_spanbuf (C++23)
strstreambuf (C++98/26*)
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Synchronized Output
basic_osyncstream (C++20)
Types
streamoff
streamsize
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Error category interface
iostream_category (C++11)
io_errc (C++11)

Public member functions
strstreambuf::strstreambuf
strstreambuf::~strstreambuf
strstreambuf::freeze
strstreambuf::str
strstreambuf::pcount
Protected member functions
strstreambuf::underflow
strstreambuf::pbackfail
strstreambuf::overflow
strstreambuf::setbuf
strstreambuf::seekoff
strstreambuf::seekpos

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Difference between revisions of "cpp/io/strstreambuf"

Latest revision as of 07:22, 6 April 2024

Contents

[edit] Notes

[edit] Member functions

Public member functions

Protected member functions

Inherited from std::basic_streambuf

Member types

Member functions

Locales

Positioning

Get area

Put area

Putback

Protected member functions

Locales

Positioning

Get area

Put area

Putback

Navigation

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