75 lines
2.6 KiB
Markdown
75 lines
2.6 KiB
Markdown
[ios.failure]
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# 31 Input/output library [[input.output]](./#input.output)
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## 31.5 Iostreams base classes [[iostreams.base]](iostreams.base#ios.failure)
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### 31.5.2 Class ios_base [[ios.base]](ios.base#ios.failure)
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#### 31.5.2.2 Types [[ios.types]](ios.types#ios.failure)
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#### 31.5.2.2.1 Class ios_base::failure [ios.failure]
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[ð](#lib:ios_base::failure)
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namespace std {class ios_base::failure : public system_error {public:explicit failure(const string& msg, const error_code& ec = io_errc::stream); explicit failure(const char* msg, const error_code& ec = io_errc::stream); };}
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[1](#1)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L919)
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An implementation is permitted to define ios_base::failure as a synonym for a class with equivalent functionality
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to class ios_base::failure shown in this subclause[.](#1.sentence-1)
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[*Note [1](#note-1)*:
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When ios_base::failure is a synonym for another type,
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that type needs to provide a nested type failure to emulate the injected-class-name[.](#1.sentence-2)
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â *end note*]
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The classfailure defines the base class
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for the types of all objects thrown as exceptions,
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by functions in the iostreams library,
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to report errors detected during stream buffer operations[.](#1.sentence-3)
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[2](#2)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L935)
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When throwing ios_base::failure exceptions, implementations should provide
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values of ec that identify the specific reason for the failure[.](#2.sentence-1)
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[*Note [2](#note-2)*:
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Errors arising from the operating system would typically be reported assystem_category() errors with an error value of the error number
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reported by the operating system[.](#2.sentence-2)
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Errors arising from within the stream library would
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typically be reported as error_code(io_errc::stream,
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iostream_category())[.](#2.sentence-3)
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â *end note*]
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[ð](#lib:ios_base::failure,constructor)
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`explicit failure(const string& msg, const error_code& ec = io_errc::stream);
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`
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[3](#3)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L952)
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*Effects*: Constructs the base class with msg and ec[.](#3.sentence-1)
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[ð](#lib:ios_base::failure,constructor_)
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`explicit failure(const char* msg, const error_code& ec = io_errc::stream);
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`
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[4](#4)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/iostreams.tex#L963)
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*Effects*: Constructs the base class with msg and ec[.](#4.sentence-1)
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