strstreambuf::seekoff
A protected virtual member function that tries to alter the current positions for the controlled streams.
virtual streampos seekoff(
streamoff _Off,
ios_base::seekdir _Way,
ios_base::openmode _Which = ios_base::in | ios_base::out
);
매개 변수
_Off
The position to seek for relative to _Way._Way
The starting point for offset operations. See seekdir for possible values._Which
Specifies the mode for the pointer position. The default is to allow you to modify the read and write positions.
반환 값
If the function succeeds in altering either or both stream positions, it returns the resultant stream position. Otherwise, it fails and returns an invalid stream position.
설명
The protected virtual member function endeavors to alter the current positions for the controlled streams. For an object of class strstreambuf, a stream position consists purely of a stream offset. Offset zero designates the first element of the controlled sequence.
The new position is determined as follows:
If _Way == ios_base::beg, the new position is the beginning of the stream plus _Off.
If _Way == ios_base::cur, the new position is the current stream position plus _Off.
If _Way == ios_base::end, the new position is the end of the stream plus _Off.
If _Which & ios_base::in is nonzero and the input buffer exist, the function alters the next position to read in the input buffer. If _Which & ios_base::out is also nonzero, _Way != ios_base::cur, and the output buffer exists, the function also sets the next position to write to match the next position to read.
Otherwise, if _Which & ios_base::out is nonzero and the output buffer exists, the function alters the next position to write in the output buffer. Otherwise, the positioning operation fails. For a positioning operation to succeed, the resulting stream position must lie within the controlled sequence.
요구 사항
Header: <strstream>
네임스페이스: std