std::streamoff (3) - Linux Man Pages
Defined in header <ios>
typedef /*unspecified*/ streamoff;
The type std::streamoff is a signed integral type of sufficient size to represent the maximum possible file size supported by the operating system. Typically, this is a typedef to long long.
It is used to represent offsets from stream positions (values of type std::fpos). A std::streamoff value of -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
fpos (class template)
seekg (public member function of std::basic_istream<CharT,Traits>)
seekp (public member function of std::basic_ostream<CharT,Traits>)