streambuf::seekpos

streampos seekpos ( streampos sp, ios_base::openmode which = ios_base::in | ios_base::out );

This member is called to set a new value for the position pointer in streambuf-derived objects. The public member function pubseekpos calls this protected member function to perform this action.

This is a virtual member function that shall be redefined in derived classes to behave as expected by setting the internal pointer specified by which to the absolute position sp.

Its default behavior in streambuf is to do nothing and return the invalid position -1, but it is redefined in both standard derived classes, filebuf and stringbuf, to behave as expected specifically for each type of buffer (see filebuf::seekpos and stringbuf::seekpos).

Parameters

sp

New absolute position for the position pointer.
This is an object of class streampos (or traits::pos_type for other traits). streampos objects may be constructed from streamoff directly from integral values representing a relative position from the beginning of the stream.

which

Determines which of the internal position pointers shall be modified: the input pointer, the output pointer, or both. It is an object of type ios_base::openmode that for this function may take any combination of the following significant constant values:

value	position pointer affected
ios_base::in	input position pointer
ios_base::out	output position pointer

Return Value

The new position value of the modified position pointer.
In case of error, the value returned shall be an invalid position, like -1.

Basic template member declaration

( basic_streambuf<charT,traits> )

See also