type
<ios> <iostream>

std::streamoff

Stream offset type
Type to represent position offsets in a stream.

It is the type returned by subtracting two stream position of an fpos type, and can be converted to and from this type.

The underlying type depends on the particular library implementation.
It is a typdef of one the fundamental signed integral types large enough to represent the maximum possible file size supported by the system.

See also

streamsize
Stream size type (type )
fpos
Stream position class template (class template )
streampos
Stream position type (type )

C++