std::fpos

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C++ Standard Library
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Input/output library
I/O manipulators C-style I/O Buffers basic_streambuf basic_filebuf basic_stringbuf strstreambuf (deprecated) Streams Abstractions ios_base basic_ios basic_istream basic_ostream basic_iostream File I/O basic_ifstream basic_ofstream basic_fstream String I/O basic_istringstream basic_ostringstream basic_stringstream Array I/O istrstream (deprecated) ostrstream (deprecated) Types streamoff streampos fpos Error category interface iostream_category (C++11) io_errc (C++11)

Defined in header <ios>
template< class State > class fpos;

Specializations of the class template std::fpos identify absolute positions in a stream or in a file. Each object of type fpos holds the byte position in the stream (typically as a private member of type std::streamoff) and the current shift state, a value of type State (typically std::mbstate_t).

Four specializations of std::fpos are provided:

Defined in header <ios>
Type	Definition
streampos	std::fpos<std::char_traits<char>::state_type>
u16streampos	std::fpos<std::char_traits<char16_t>::state_type>
u32streampos	std::fpos<std::char_traits<char32_t>::state_type>
wstreampos	std::fpos<std::char_traits<wchar_t>::state_type>

[edit] Member functions

state	gets/sets the value of the shift state (public member function)

In addition, the following member functions and operators must be provided, altbough it's unspecified if they are members or non-member.

• A constructor that accepts an argument of type int.

• A constructor that accepts an argument of type std::streamoff. This constructor must also accept the special value std::streamoff(-1): the std::fpos constructed in this manner is returned by some stream operations to indicate errors.

• A conversion operator that converts fpos to std::streamoff with the value equal to the offset from std::fpos(0).

• operator== that compares two objects of type std::fpos and returns a value of type convertible to bool

• operator!= that compares two objects of type std::fpos and returns a value of type convertible to bool

• operator+ and operator+= which can add std::streamoff to std::fpos

• operator- and opeartor-= which can subtract std::streamoff from an std::fpos

• operator- which can subtract two objects of type std::fpos producing an std::streamoff

[edit] See also

streamoff	represents relative file/stream position (offset from fpos), sufficient to represent any file size (typedef)
tellp	returns the output position indicator (public member function)
seekp	sets the output position indicator (public member function)
fgetpos	gets the file position indicator (function)