std::streamoff

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