protected virtual member function
<streambuf> <iostream>


pos_type seekoff (off_type off, ios_base::seekdir way,
Set internal position pointer to relative position
Virtual function called by the public member function pubseekoff to alter the stream positions of one or more of the controlled sequences in a specific way for each derived class.

Its default behavior in basic_streambuf is to do nothing and return -1, but derived classes shall override this behavior to alter the internal pointers appropriately: both basic_filebuf and basic_stringbuf override this virtual member function to set the internal pointer specified by which to a position offset off relative to the direction specified by way.


Offset value, relative to the way parameter.
Member type off_type is determined by the character traits: generally, it is an alias of the signed integral type streamoff.
Object of type ios_base::seekdir. It may take any of the following constant values:
valueoffset is relative to...
ios_base::begbeginning of the stream buffer
ios_base::curcurrent position in the stream buffer
ios_base::endend of the stream buffer
Generally used to determine the position on which of the controlled sequences shall be modified: the input sequence, the output sequence, 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:
valueposition pointer affected
ios_base::inModify current position in controlled input sequence
ios_base::outModify current position in controlled output sequence

Return Value

Returns pos_type(off_type(-1)).
Member type pos_type is determined by the character traits: generally, it is an fpos type (such as streampos) that can be converted to/from integral types.

Data races


Exception safety

No-throw guarantee: this default definition never throws exceptions.

See also