The class describes the storage and member functions common to both input and output streams that do not depend on the template parameters. (The template class basic_ios describes what is common and is dependent on template parameters.)
An object of class ios_base stores formatting information, which consists of:
Format flags in an object of type fmtflags.
An exception mask in an object of type iostate.
A field width in an object of type int.
A display precision in an object of type int.
A locale object in an object of type locale.
Two extensible arrays, with elements of type long and void pointer.
An object of class ios_base also stores stream state information, in an object of type iostate, and a callback stack.
A bitmask defined as internal | left | right.
Specifies seeking to the end of a stream before each insertion.
Specifies seeking to the end of a stream when its controlling object is first created.
Records a loss of integrity of the stream buffer.
A bitmask defined as dec | hex | oct.
Specifies seeking relative to the beginning of a sequence.
Specifies that a file should be read as a binary stream, rather than as a text stream.
Specifies insertion or extraction of objects of type bool as names (such as true and false) rather than as numeric values.
Specifies seeking relative to the current position within a sequence.
Specifies insertion or extraction of integer values in decimal format.
Specifies seeking relative to the end of a sequence.
Records end-of-file while extracting from a stream.
Records a failure to extract a valid field from a stream.
Specifies insertion of floating-point values in fixed-point format (with no exponent field).
A bitmask defined as fixed | scientific
All state bits clear.
Specifies insertion or extraction of integer values in hexadecimal format.
Specifies extraction from a stream.
Pads to a field width by inserting fill characters at a point internal to a generated numeric field.
Specifies left justification.
Specifies insertion or extraction of integer values in octal format.
Specifies insertion to a stream.
Specifies right justification.
Specifies insertion of floating-point values in scientific format (with an exponent field).
Specifies insertion of a prefix that reveals the base of a generated integer field.
Specifies unconditional insertion of a decimal point in a generated floating-point field.
Specifies insertion of a plus sign in a nonnegative generated numeric field.
Specifies skipping leading white space before certain extractions.
Specifies deleting contents of an existing file when its controlling object is created.
Causes output to be flushed after each insertion.
Specifies insertion of uppercase equivalents of lowercase letters in certain insertions.
Sets or returns the current flag settings.
Returns the stored locale object.
Changes the locale.
Creates the standard iostream objects when constructed.
Assigns a value to be stored as an iword.
Specifies the number of digits to display in a floating-point number.
Assigns a value to be stored as a pword.
Specifies a callback function.
Sets the specified flags.
Ensures that iostream and C run-time library operations occur in the order that they appear in source code.
Causes the specified flags to be off.
Sets the length of the output stream.
Specifies that a variable shall be part of the stream.