filebuf::seekoff


virtual protected member function
streampos seekoff ( streamoff off, ios_base::seekdir way, ios_base::openmode which = ios_base::in | ios_base::out );

Set internal position pointer to relative position

Sets a new position to the position pointers specified by parameter which. This position is made from an offset value (off) relative to a given direction (way).

If the which parameter includes ios_base::in, the get pointer gptr is affected, and if the which parameter includes ios_base::out, the put pointer pptr. Both position pointers can be affected by a single call.

This member function overrides the virtual member streambuf::seekoff, which is called by member streambuf::pubseekoff.

Parameters

off
Offset value. This is relative to the way parameter.
It is a value of type streamoff.
way
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
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:
valueposition pointer affected
ios_base::inModify get pointer position
ios_base::outModify put pointer position


Return Value

The new position value of the modified position pointer. If the position was invalid, the function returns a value of -1 to signal failure.

Basic template member declaration

( basic_filebuf<charT,traits,Allocator> )
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typedef traits::pos_type pos_type;
typedef traits::off_type off_type;
pos_type seekoff (off_type off, ios_base::seekdir way, ios_base which = ios_base::in | ios_base::out );


See also

filebuf::seekpos Set internal position pointer to absolute position (virtual protected member function)
streambuf::pubseekoff Set internal position pointer to relative position (public member function)