[#bsl-basic_stringbuf]
= xref:bsl.adoc[bsl]::basic_stringbuf
:relfileprefix: ../
:mrdocs:

This class implements a standard stream buffer providing an unformatted character input sequence and an unformatted character output sequence that may be initialized or accessed using a string value.

== Synopsis

Declared in `<bslstl_stringbuf.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
template<
    class CHAR_TYPE,
    class CHAR_TRAITS = char_traits<CHAR_TYPE>,
    class ALLOCATOR = xref:bsl/allocator-0df.adoc[allocator<CHAR_TYPE>]>
class basic_stringbuf
    : public std::basic_streambuf<CHAR_TYPE, CHAR_TRAITS>
----

== Base Classes

[cols="1,4"]
|===
| Name| Description
| `std::basic_streambuf<CHAR_TYPE, CHAR_TRAITS>`
| The actual work of input and output (interface).
|===

== Type Aliases

[cols="1,4"]
|===
| Name| Description
| xref:bsl/basic_stringbuf/__streambuf_type.adoc[`__streambuf_type`] 
| @{ This is a non‐standard type.
| xref:bsl/basic_stringbuf/allocator_type.adoc[`allocator_type`] 
| This `typedef` is an alias to the (template parameter) `ALLOCATOR`.
| xref:bsl/basic_stringbuf/char_type.adoc[`char_type`] 
| This `typedef` is an alias to the (template parameter) `CHAR_TYPE`.
| xref:bsl/basic_stringbuf/int_type.adoc[`int_type`] 
| This `typedef` is an alias to `traits_type::int_type`.
| xref:bsl/basic_stringbuf/off_type.adoc[`off_type`] 
| This `typedef` is an alias to `traits_type::off_type`.
| xref:bsl/basic_stringbuf/pos_type.adoc[`pos_type`] 
| This `typedef` is an alias to `traits_type::pos_type`.
| xref:bsl/basic_stringbuf/traits_type.adoc[`traits_type`] 
| This `typedef` is an alias to the (template parameter) `CHAR_TRAITS`.
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:bsl/basic_stringbuf/2constructor-0d2.adoc[`basic_stringbuf`]         [.small]#[constructor]#
| Constructors
| xref:bsl/basic_stringbuf/2destructor.adoc[`~basic_stringbuf`] [.small]#[destructor]#
| Destroy this object.
| xref:bsl/basic_stringbuf/operator_assign-02.adoc[`operator=`] 
| Assign to this object the value of the specified `rhs`, and return a reference providing modifiable access to this object. The contents of `rhs` are move‐assigned to this object. `rhs` is left in a valid but unspecified state.
| xref:bsl/basic_stringbuf/get_allocator.adoc[`get_allocator`] 
| Return the allocator used by the underlying string to supply memory.
| xref:bsl/basic_stringbuf/getloc.adoc[`getloc`] 
| Locale access.
| xref:bsl/basic_stringbuf/in_avail.adoc[`in_avail`] 
| Looking ahead into the stream.
| xref:bsl/basic_stringbuf/pubimbue.adoc[`pubimbue`] 
| Entry point for imbue().
| xref:bsl/basic_stringbuf/pubseekoff.adoc[`pubseekoff`] 
| Alters the stream position.
| xref:bsl/basic_stringbuf/pubseekpos.adoc[`pubseekpos`] 
| Alters the stream position.
| xref:bsl/basic_stringbuf/pubsetbuf.adoc[`pubsetbuf`] 
| Entry points for derived buffer functions.
| xref:bsl/basic_stringbuf/pubsync.adoc[`pubsync`] 
| Calls virtual sync function.
| xref:bsl/basic_stringbuf/sbumpc.adoc[`sbumpc`] 
| Getting the next character.
| xref:bsl/basic_stringbuf/sgetc.adoc[`sgetc`] 
| Getting the next character.
| xref:bsl/basic_stringbuf/sgetn.adoc[`sgetn`] 
| Entry point for xsgetn.
| xref:bsl/basic_stringbuf/snextc.adoc[`snextc`] 
| Getting the next character.
| xref:bsl/basic_stringbuf/sputbackc.adoc[`sputbackc`] 
| Pushing characters back into the input stream.
| xref:bsl/basic_stringbuf/sputc.adoc[`sputc`] 
| Entry point for all single‐character output functions.
| xref:bsl/basic_stringbuf/sputn.adoc[`sputn`] 
| Entry point for all single‐character output functions.
| xref:bsl/basic_stringbuf/str-0d9.adoc[`str`] 
| `str` overloads
| xref:bsl/basic_stringbuf/sungetc.adoc[`sungetc`] 
| Moving backwards in the input stream.
| xref:bsl/basic_stringbuf/swap-08.adoc[`swap`] 
| Efficiently exchange the value of this object with the value of the specified `other` object. This method provides the no‐throw exception‐safety guarantee if `*this` and `other` allocators compare equal. The behavior is undefined unless either `*this` and `other` allocators compare equal or `propagate_on_container_swap` is `true`. Note that this function is only available for C++11 (and later) language standards because it requires that `swap` be provided on the (platform supplied) base class for this type.
| xref:bsl/basic_stringbuf/view.adoc[`view`] 
| Return a `string_view` containing the currently buffered sequence of characters. If this object was created only in input mode, the resultant `ViewType` contains the character sequence in the range `[eback(), egptr())]`. If `modeBitMask & ios_base::out` specified at construction is nonzero then the resultant `StringType` contains the character sequence in the range `[pbase(), high_mark)]`, where `high_mark` represents the position one past the highest initialized character in the buffer. Otherwise this object has been created in neither input nor output mode and a zero length `ViewType` is returned.
|===


== Protected Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:bsl/basic_stringbuf/operator_assign-0b.adoc[`operator=`] 
| 
| xref:bsl/basic_stringbuf/__safe_gbump.adoc[`__safe_gbump`] 
| 
| xref:bsl/basic_stringbuf/__safe_pbump.adoc[`__safe_pbump`] 
| 
| xref:bsl/basic_stringbuf/eback.adoc[`eback`] 
| Access to the get area.
| xref:bsl/basic_stringbuf/egptr.adoc[`egptr`] 
| 
| xref:bsl/basic_stringbuf/epptr.adoc[`epptr`] 
| 
| xref:bsl/basic_stringbuf/gbump.adoc[`gbump`] 
| Moving the read position.
| xref:bsl/basic_stringbuf/gptr.adoc[`gptr`] 
| 
| xref:bsl/basic_stringbuf/imbue.adoc[`imbue`]  [.small]#[virtual]#
| Changes translations.
| xref:bsl/basic_stringbuf/overflow-090.adoc[`overflow`] 
| `overflow` overloads
| xref:bsl/basic_stringbuf/pbackfail-07.adoc[`pbackfail`] 
| `pbackfail` overloads
| xref:bsl/basic_stringbuf/pbase.adoc[`pbase`] 
| Access to the put area.
| xref:bsl/basic_stringbuf/pbump.adoc[`pbump`] 
| Moving the write position.
| xref:bsl/basic_stringbuf/pptr.adoc[`pptr`] 
| 
| xref:bsl/basic_stringbuf/seekoff-00.adoc[`seekoff`] 
| `seekoff` overloads
| xref:bsl/basic_stringbuf/seekpos-05.adoc[`seekpos`] 
| `seekpos` overloads
| xref:bsl/basic_stringbuf/setbuf.adoc[`setbuf`]  [.small]#[virtual]#
| Manipulates the buffer.
| xref:bsl/basic_stringbuf/setg.adoc[`setg`] 
| Setting the three read area pointers.
| xref:bsl/basic_stringbuf/setp.adoc[`setp`] 
| Setting the three write area pointers.
| xref:bsl/basic_stringbuf/showmanyc.adoc[`showmanyc`]  [.small]#[virtual]#
| Investigating the data available.
| xref:bsl/basic_stringbuf/swap-00.adoc[`swap`] 
| 
| xref:bsl/basic_stringbuf/sync.adoc[`sync`]  [.small]#[virtual]#
| Synchronizes the buffer arrays with the controlled sequences.
| xref:bsl/basic_stringbuf/uflow.adoc[`uflow`]  [.small]#[virtual]#
| Return the character at the current input position and advance the input position by 1. If no character is available at the current input position, return `traits_type::eof()`. Update the end of the input area, `egptr`, if additional characters are available (as may occur if additional characters have been written to the string buffer). Note that this operation is similar to `underflow`, but advances the current input position.
| xref:bsl/basic_stringbuf/underflow.adoc[`underflow`]  [.small]#[virtual]#
| Return the character at the current input position, if a character is available, and `traits_type::eof()` otherwise. Update the end of the input area, `egptr`, if additional characters are available (as may occur if additional characters have been written to the string buffer). Note that this operation is similar to `uflow`, but does not advance the current input position.
| xref:bsl/basic_stringbuf/xsgetn-09.adoc[`xsgetn`] 
| `xsgetn` overloads
| xref:bsl/basic_stringbuf/xsputn-06.adoc[`xsputn`] 
| `xsputn` overloads
|===


== Protected Data Members

[cols="1,4"]
|===
| Name| Description
| xref:bsl/basic_stringbuf/_M_buf_locale.adoc[`_M_buf_locale`] 
| Current locale setting.
| xref:bsl/basic_stringbuf/_M_in_beg.adoc[`_M_in_beg`] 
| Start of get area.
| xref:bsl/basic_stringbuf/_M_in_cur.adoc[`_M_in_cur`] 
| Current read area.
| xref:bsl/basic_stringbuf/_M_in_end.adoc[`_M_in_end`] 
| End of get area.
| xref:bsl/basic_stringbuf/_M_out_beg.adoc[`_M_out_beg`] 
| Start of put area.
| xref:bsl/basic_stringbuf/_M_out_cur.adoc[`_M_out_cur`] 
| Current put area.
| xref:bsl/basic_stringbuf/_M_out_end.adoc[`_M_out_end`] 
| End of put area.
|===


== Non-Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:bsl/swap-06f.adoc[`swap`]
| Efficiently exchange the values of the specified `a` and `b` objects. This method provides the no‐throw exception‐safety guarantee if `a` and `b` allocators compare equal. Note that this function is only available for C++11 (and later) language standards.
|===


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