class template


template < class charT, class traits = char_traits<charT> >
  class basic_ifstream;
Input file stream

Input stream class to operate on files.

Objects of this class maintain a basic_filebuf object as their internal stream buffer, which performs input/output operations on the file they are associated with (if any).

File streams are associated with files either on construction, or by calling member open.

Apart from the internal file stream buffer, objects of these classes keep a set of internal fields inherited from ios_base, basic_ios and basic_istream:

fieldmember functionsdescription
Formattingformat flagsflags
A set of internal flags that affect how certain input/output operations are interpreted or generated.
See member type fmtflags.
field widthwidthWidth of the next formatted element to insert.
display precisionprecisionDecimal precision for the next floating-point value inserted.
The locale object used by the function for formatted input/output operations affected by localization properties.
fill characterfillCharacter to pad a formatted field up to the field width (width).
Stateerror staterdstate
The current error state of the stream.
Individual values may be obtained by calling good, eof, fail and bad.
See member type iostate.
exception maskexceptionsThe state flags for which a failure exception is thrown.
See member type iostate.
Othercallback stackregister_callbackStack of pointers to functions that are called when certain events occur.
extensible arraysiword
Internal arrays to store objects of type long and void*.
tied streamtiePointer to output stream that is flushed before each i/o operation on this stream.
stream bufferrdbufPointer to the associated basic_streambuf object, which is charge of all input/output operations.
character countgcountCount of characters read by last unformatted input operation (input streams only).

Template parameters

Character type.
This shall be a non-array POD type.
Aliased as member type basic_ifstream::char_type.
Character traits class that defines essential properties of the characters used by stream object (see char_traits).
traits::char_type shall be the same as charT.
Aliased as member type basic_ifstream::traits_type.

Template instantiations

These instantiations are declared in <fstream>.

Member types

The class declares the following member types:
member typedefinitionnotes
char_typeThe first template parameter (charT)
traits_typeThe second template parameter (traits)defaults to: char_traits<charT>
pos_typetraits_type::pos_typegenerally, the same as streampos
off_typetraits_type::off_typegenerally, the same as streamoff

These member types are inherited from its base classes basic_istream and ios_base:

Public member functions

Public member functions inherited from basic_istream

Public member functions inherited from basic_ios

Public member functions inherited from ios_base

Non-member function overloads