102 lines
3.0 KiB
Markdown
102 lines
3.0 KiB
Markdown
[syncstream.syncbuf.members]
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# 31 Input/output library [[input.output]](./#input.output)
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## 31.11 Synchronized output streams [[syncstream]](syncstream#syncbuf.members)
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### 31.11.2 Class template basic_syncbuf [[syncstream.syncbuf]](syncstream.syncbuf#members)
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#### 31.11.2.4 Member functions [syncstream.syncbuf.members]
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[ð](#lib:emit,basic_syncbuf)
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`bool emit();
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`
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[1](#1)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12802)
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*Effects*: Atomically transfers the associated output of *this to the stream buffer **wrapped*,
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so that it appears in the output stream
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as a contiguous sequence of characters[.](#1.sentence-1)
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*wrapped*->pubsync() is called
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if and only if a call was made to sync() since the most recent call to emit(), if any[.](#1.sentence-2)
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[2](#2)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12812)
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*Synchronization*: All emit() calls transferring characters
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to the same stream buffer object
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appear to execute in a total order
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consistent with the âhappens beforeâ relation ([[intro.races]](intro.races "6.10.2.2 Data races")),
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where each emit() call
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synchronizes with
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subsequent emit() calls in that total order[.](#2.sentence-1)
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[3](#3)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12822)
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*Postconditions*: On success, the associated output is empty[.](#3.sentence-1)
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[4](#4)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12826)
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*Returns*: true if all of the following conditions hold;
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otherwise false:
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- [(4.1)](#4.1)
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*wrapped* == nullptr is false[.](#4.1.sentence-1)
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- [(4.2)](#4.2)
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All of the characters in the associated output were successfully transferred[.](#4.2.sentence-1)
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- [(4.3)](#4.3)
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The call to *wrapped*->pubsync() (if any) succeeded[.](#4.3.sentence-1)
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[5](#5)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12836)
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*Remarks*: May call member functions of *wrapped* while holding a lock uniquely associated with *wrapped*[.](#5.sentence-1)
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[ð](#lib:get_wrapped,basic_syncbuf)
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`streambuf_type* get_wrapped() const noexcept;
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`
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[6](#6)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12848)
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*Returns*: *wrapped*[.](#6.sentence-1)
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[ð](#lib:get_allocator,basic_syncbuf)
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`allocator_type get_allocator() const noexcept;
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`
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[7](#7)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12859)
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*Returns*: A copy of the allocator that was set in the constructor or assignment operator[.](#7.sentence-1)
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[ð](#lib:set_emit_on_sync,basic_syncbuf)
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`void set_emit_on_sync(bool b) noexcept;
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`
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[8](#8)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L12870)
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*Effects*: *emit-on-sync* = b[.](#8.sentence-1)
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