protected virtual member function
<fstream>
streampos seekpos (streampos pos, ios_base::openmode which = ios_base::in | ios_base::out);
Set position pointer to absolute position
Sets the absolute new position pos for the internal position pointers specified by parameter which.
If which includes out, the function also writes any unwritten characters in the intermediate output buffer to the file (also calling unshift using the proper facet, when needed).
This virtual function is called by the public member streambuf::pubseekpos.
Parameters
- pos
- New absolute position for the position pointer.
streamoff is a signed integral type.
- which
- Determines which of the internal position pointers is affected: the input position, the output position, 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 | Modifies the input position, and its corresponding get pointer (gptr) |
| ios_base::out | Modifies the output position and its corresponding put pointer (pptr) |
Both positions may be selected simultaneously.
Return Value
On success, it returns pos.
On failure, the function returns streampos(streamoff(-1)).
streampos is a positioning type that can be converted to/from integral types (an fpos type).
Data races
Modifies the filebuf object.
Concurrent access to the same file stream buffer object may introduce data races.
Exception safety
Basic guarantee: if an exception is thrown, the file stream buffer is in a valid state.
See also
- filebuf::seekoff
- Set internal position to relative position (protected virtual member function)
- streambuf::pubseekpos
- Set internal position pointer to absolute position (public member function)