std::streamoff

 

C++

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Synchronized Output

basic_osyncstream (C++20)

Types

streamoff

streamsize

fpos

Error category interface

iostream_category (C++11)

io_errc (C++11)

 

Defined in header <ios>
typedef /*implementation-defined*/ streamoff;

The type std::streamoff is an implementation-defined signed integral(since C++11) type of sufficient size to represent the maximum possible file size supported by the operating system. Typically, this is an alias for long long.(since C++11)

It is used to represent offsets from stream positions (values of type std::fpos). A std::streamoff value constructed from -1 is also used to represent error conditions by some of the I/O library functions.

Relationship with std::fpos

• the difference between two std::fpos objects is a value of type std::streamoff

• a value of type std::streamoff may be added or subtracted from std::fpos yielding a different std::fpos.

• a value of type std::fpos is implicitly convertible to std::streamoff (the conversion result is the offset from the beginning of the file).

• a value of type std::fpos is constructible from a value of type std::streamoff

See also

fpos	represents absolute position in a stream or a file (class template)
seekg	sets the input position indicator (public member function of std::basic_istream<CharT,Traits>)
seekp	sets the output position indicator (public member function of std::basic_ostream<CharT,Traits>)