stream_position/[2,3]

Module: sio

stream_position/[2,3] — reposition a stream

FORMS

set_stream_position(Stream_or_alias, Current_position, New_position)

DESCRIPTION

If the stream associated with Stream_or_alias supports repositioning, Current_position is unified with the current stream position of the stream, and, as a side effect, the stream position of this stream is set to the position represented by New_position. New_position may be one of the following values:

• An absolute integer which represents the address of a character in the stream. The beginning of the stream or the first character in the stream has position 0 The second character in the stream has position 1 and so on.
• The atom beginning_of_stream.
• The term beginning_of_stream(N) where N is an integer greater than zero. The position represented by this term is the beginning of the stream plus N bytes.
• The atom end_of_stream.
• The term end_of_stream(N) where N is an integer less than or equal to zero. This allows positions (earlier than the end of stream) to be specified relative to the end of the stream. The position represented by this term is the end-of-stream position plus N bytes.
• The atom current_position.
• The term current_position(N) where N is an integer. This allows positions to be specified relative to the current position in the file.

ERRORS

Stream_or_Alias is a variable

– – – – > instantiation_error

New_Position is a variable

– – – – > instantiation_error

Stream_or_Alias is neither a variable nor a stream descriptor nor an alias

– – – – > domain_error(stream_position, Position)

New_Position is neither a variable nor a stream position

– – – – > domain_error(stream_position, Position)

Stream_or_Alias is not associated with an open stream

– – – – > existence_error(stream, Stream_or_Alias)

Stream_or_Alias has stream property reposition(false)

– – – – > permission_error(reposition, stream, Stream_or_Alias)