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

Forward declaration of `basic_syncbuf`.

== Synopsis

Declared in `<bslstl_syncbuf.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_syncbuf
    : public std::basic_streambuf<CHAR_TYPE, CHAR_TRAITS>
    , public xref:BloombergLP/bslstl/SyncBufBase.adoc[BloombergLP::bslstl::SyncBufBase]
----

== Base Classes

[cols="1,4"]
|===
| Name| Description
| `std::basic_streambuf<CHAR_TYPE, CHAR_TRAITS>`
| The actual work of input and output (interface).
| `xref:BloombergLP/bslstl/SyncBufBase.adoc[BloombergLP::bslstl::SyncBufBase]`
| Allocator‐independent base of `basic_syncbuf`. Also this is used by the manipulators: `emit_on_flush`, `noemit_on_flush`, `flush_emit` (the `ALLOCATOR` template argument cannot be deduced from `basic_ostream<CHAR_TYPE, CHAR_TRAITS>`).
|===

== Type Aliases

[cols="1,4"]
|===
| Name| Description
| xref:bsl/basic_syncbuf/__streambuf_type.adoc[`__streambuf_type`] 
| @{ This is a non‐standard type.
| xref:bsl/basic_syncbuf/allocator_type.adoc[`allocator_type`] 
| Allocator type used by this stream buffer.
| xref:bsl/basic_syncbuf/char_type.adoc[`char_type`] 
| Character type manipulated by this stream buffer.
| xref:bsl/basic_syncbuf/int_type.adoc[`int_type`] 
| Integer type returned by stream operations.
| xref:bsl/basic_syncbuf/off_type.adoc[`off_type`] 
| Offset type used by the character traits.
| xref:bsl/basic_syncbuf/pos_type.adoc[`pos_type`] 
| Position type used by the character traits.
| xref:bsl/basic_syncbuf/streambuf_type.adoc[`streambuf_type`] 
| Stream buffer type wrapped by this synchronized buffer.
| xref:bsl/basic_syncbuf/traits_type.adoc[`traits_type`] 
| Character traits type used by this stream buffer.
|===


== Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:bsl/basic_syncbuf/2constructor-0a.adoc[`basic_syncbuf`]         [.small]#[constructor]#
| Constructors
| xref:bsl/basic_syncbuf/2destructor.adoc[`~basic_syncbuf`] [.small]#[destructor]# [.small]#[virtual]#
| Call `emit`. Any exceptions thrown by `emit` are ignored.
| xref:bsl/basic_syncbuf/operator_assign-0e.adoc[`operator=`] 
| Call `emit()` then assign to this object the value of the specified `original`, and return a reference providing modifiable access to this object. The contents of `original` are move‐assigned to this object. `original.get_wrapped() == nullptr` after the call.
| xref:bsl/basic_syncbuf/emit.adoc[`emit`] 
| Atomically transfer any characters buffered by this object to the wrapped stream buffer, so that it appears in the output stream as a contiguous sequence of characters. The wrapped stream buffer is flushed if and only if a call was made to `sync` since the most recent call to `emit` or construction. Return `true` if `get_wrapped() != nullptr`, and all of the characters in the associated output were successfully transferred, and the flush (if any) succeeded; return `false` otherwise.
| xref:bsl/basic_syncbuf/get_allocator.adoc[`get_allocator`] 
| Return the allocator used to supply memory.
| xref:bsl/basic_syncbuf/get_wrapped.adoc[`get_wrapped`] 
| Return the wrapped buffer supplied at construction.
| xref:bsl/basic_syncbuf/getloc.adoc[`getloc`] 
| Locale access.
| xref:bsl/basic_syncbuf/in_avail.adoc[`in_avail`] 
| Looking ahead into the stream.
| xref:bsl/basic_syncbuf/pubimbue.adoc[`pubimbue`] 
| Entry point for imbue().
| xref:bsl/basic_syncbuf/pubseekoff.adoc[`pubseekoff`] 
| Alters the stream position.
| xref:bsl/basic_syncbuf/pubseekpos.adoc[`pubseekpos`] 
| Alters the stream position.
| xref:bsl/basic_syncbuf/pubsetbuf.adoc[`pubsetbuf`] 
| Entry points for derived buffer functions.
| xref:bsl/basic_syncbuf/pubsync.adoc[`pubsync`] 
| Calls virtual sync function.
| xref:bsl/basic_syncbuf/sbumpc.adoc[`sbumpc`] 
| Getting the next character.
| xref:bsl/basic_syncbuf/set_emit_on_sync.adoc[`set_emit_on_sync`] 
| Call the `emit` function by each `sync` call if the specified `value` is `true`.
| xref:bsl/basic_syncbuf/sgetc.adoc[`sgetc`] 
| Getting the next character.
| xref:bsl/basic_syncbuf/sgetn.adoc[`sgetn`] 
| Entry point for xsgetn.
| xref:bsl/basic_syncbuf/snextc.adoc[`snextc`] 
| Getting the next character.
| xref:bsl/basic_syncbuf/sputbackc.adoc[`sputbackc`] 
| Pushing characters back into the input stream.
| xref:bsl/basic_syncbuf/sputc.adoc[`sputc`] 
| Entry point for all single‐character output functions.
| xref:bsl/basic_syncbuf/sputn.adoc[`sputn`] 
| Entry point for all single‐character output functions.
| xref:bsl/basic_syncbuf/sungetc.adoc[`sungetc`] 
| Moving backwards in the input stream.
| xref:bsl/basic_syncbuf/swap-05.adoc[`swap`] 
| Efficiently exchange the value of this object with the value of the specified `other` object. The behavior is undefined unless either `*this` and `other` allocators compare equal or `propagate_on_container_swap` is `true`.
|===


== Protected Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:bsl/basic_syncbuf/operator_assign-09.adoc[`operator=`] 
| 
| xref:bsl/basic_syncbuf/__safe_gbump.adoc[`__safe_gbump`] 
| 
| xref:bsl/basic_syncbuf/__safe_pbump.adoc[`__safe_pbump`] 
| 
| xref:bsl/basic_syncbuf/eback.adoc[`eback`] 
| Access to the get area.
| xref:bsl/basic_syncbuf/egptr.adoc[`egptr`] 
| 
| xref:bsl/basic_syncbuf/epptr.adoc[`epptr`] 
| 
| xref:bsl/basic_syncbuf/gbump.adoc[`gbump`] 
| Moving the read position.
| xref:bsl/basic_syncbuf/gptr.adoc[`gptr`] 
| 
| xref:bsl/basic_syncbuf/imbue.adoc[`imbue`]  [.small]#[virtual]#
| Changes translations.
| xref:bsl/basic_syncbuf/overflow-05.adoc[`overflow`] 
| `overflow` overloads
| xref:bsl/basic_syncbuf/pbackfail.adoc[`pbackfail`]  [.small]#[virtual]#
| Tries to back up the input sequence.
| xref:bsl/basic_syncbuf/pbase.adoc[`pbase`] 
| Access to the put area.
| xref:bsl/basic_syncbuf/pbump.adoc[`pbump`] 
| Moving the write position.
| xref:bsl/basic_syncbuf/pptr.adoc[`pptr`] 
| 
| xref:bsl/basic_syncbuf/seekoff.adoc[`seekoff`]  [.small]#[virtual]#
| Alters the stream positions.
| xref:bsl/basic_syncbuf/seekpos.adoc[`seekpos`]  [.small]#[virtual]#
| Alters the stream positions.
| xref:bsl/basic_syncbuf/setbuf.adoc[`setbuf`]  [.small]#[virtual]#
| Manipulates the buffer.
| xref:bsl/basic_syncbuf/setg.adoc[`setg`] 
| Setting the three read area pointers.
| xref:bsl/basic_syncbuf/setp.adoc[`setp`] 
| Setting the three write area pointers.
| xref:bsl/basic_syncbuf/showmanyc.adoc[`showmanyc`]  [.small]#[virtual]#
| Investigating the data available.
| xref:bsl/basic_syncbuf/swap-07.adoc[`swap`] 
| 
| xref:bsl/basic_syncbuf/sync.adoc[`sync`] 
| Request the wrapped streambuf flush on the next `emit` call, then call `emit` if the "emit‐on‐sync" flag is `true`. Return 0 on success and ‐1 if the `emit` call has failed.
| xref:bsl/basic_syncbuf/uflow.adoc[`uflow`]  [.small]#[virtual]#
| Fetches more data from the controlled sequence.
| xref:bsl/basic_syncbuf/underflow.adoc[`underflow`]  [.small]#[virtual]#
| Fetches more data from the controlled sequence.
| xref:bsl/basic_syncbuf/xsgetn.adoc[`xsgetn`]  [.small]#[virtual]#
| Multiple character extraction.
| xref:bsl/basic_syncbuf/xsputn-00.adoc[`xsputn`] 
| `xsputn` overloads
|===


== Protected Data Members

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


== Non-Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:bsl/swap-0a4.adoc[`swap`]
| Swap the specified `a` with the specified `b` using `a.swap(b)` expression.
|===


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