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/C++std::basic_ios
Defined in header <ios> | ||
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template<
class CharT,
class Traits = std::char_traits<CharT>
> class basic_ios : public std::ios_base
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The class std::basic_ios provides facilities for interfacing with objects that have std::basic_streambuf interface. Several std::basic_ios objects can refer to one actual std::basic_streambuf object.
Inheritance diagram.
Two specializations for common character types are also provided:
| Type | Definition |
|---|---|
ios | basic_ios<char> |
wios | basic_ios<wchar_t> |
Member types
| Member type | Definition |
|---|---|
char_type | CharT
|
traits_type | Traits; the program is ill-formed if Traits::char_type is not CharT. |
int_type | Traits::int_type
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pos_type | Traits::pos_type
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off_type | Traits::off_type
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Public member functions
| constructs the object (public member function) |
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[virtual] | destructs the object (virtual public member function) |
| operator= | the copy assignment operator is deleted (public member function) |
State functions |
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| checks if no error has occurred i.e. I/O operations are available (public member function) |
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| checks if end-of-file has been reached (public member function) |
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| checks if an error has occurred (public member function) |
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| checks if a non-recoverable error has occurred (public member function) |
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checks if an error has occurred (synonym of fail()) (public member function) |
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(until C++11)(since C++11) | checks if no error has occurred (synonym of !fail()) (public member function) |
| returns state flags (public member function) |
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| sets state flags (public member function) |
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| modifies state flags (public member function) |
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Formatting |
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| copies formatting information (public member function) |
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| manages the fill character (public member function) |
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Miscellaneous |
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| manages exception mask (public member function) |
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| sets the locale (public member function) |
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| manages associated stream buffer (public member function) |
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| manages tied stream (public member function) |
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| narrows characters (public member function) |
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| widens characters (public member function) |
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Protected member functions
initializes a default-constructed std::basic_ios (protected member function) |
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(C++11) | moves from another std::basic_ios except for rdbuf (protected member function) |
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(C++11) | swaps with another std::basic_ios except for rdbuf (protected member function) |
replaces the rdbuf without clearing its error state (protected member function) |
Inherited from std::ios_base
Member functions
Formatting |
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| manages format flags (public member function of std::ios_base) |
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| sets specific format flag (public member function of std::ios_base) |
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| clears specific format flag (public member function of std::ios_base) |
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| manages decimal precision of floating point operations (public member function of std::ios_base) |
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| manages field width (public member function of std::ios_base) |
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Locales |
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| sets locale (public member function of std::ios_base) |
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| returns current locale (public member function of std::ios_base) |
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Internal extensible array |
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[static] | returns a program-wide unique integer that is safe to use as index to pword() and iword() (public static member function of std::ios_base) |
resizes the private storage if necessary and access to the long element at the given index (public member function of std::ios_base) |
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resizes the private storage if necessary and access to the void* element at the given index (public member function of std::ios_base) |
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Miscellaneous |
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| registers event callback function (public member function of std::ios_base) |
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[static] | sets whether C++ and C IO libraries are interoperable (public static member function of std::ios_base) |
Member classes |
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| stream exception (public member class of std::ios_base) |
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| initializes standard stream objects (public member class of std::ios_base) |
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Member types and constants |
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| Type | Explanation | ||||||||||||||||||||||||||||||||||||||
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| stream open mode type The following constants are also defined:
(typedef) |
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| formatting flags type The following constants are also defined:
(typedef) |
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| state of the stream type The following constants are also defined:
(typedef) |
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| seeking direction type The following constants are also defined:
(typedef) |
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| specifies event type (enum) |
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| callback function type (typedef) |
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Notes
Straightforward implementation of std::basic_ios stores only the following members (which all depend on the template parameters and thus cannot be part of std::ios_base):
- the fill character (see
fill()) - the tied stream pointer (see
tie()) - the associated stream buffer pointer (see
rdbuf())
Actual implementations vary:
Microsoft Visual Studio stores just those three members.
LLVM libc++ stores 1 less member: it maintains the rdbuf pointer as a void* member of ios_base.
GNU libstdc++ stores 4 additional members: three cached facets and a flag to indicate that fill was initialized.
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