fseek - change the current read/write position in a File
file.fseek(
offs,
whence)
The fseek()
intrinsic method sets the current
read/write position in a file. The new position is obtained by adding
offs bytes to the position specified by whence:
whence | Meaning |
---|---|
io::SEEK_SET | Relative to beginning of file |
io::SEEK_CUR | Relative to current read/write position |
io::SEEK_END | Relative to end-of-file |
offs may be an Int
or a
Long
. The current read/write position may be
obtained with the ftell()
intrinsic method. A
successful fseek()
will clear the end-of-file
indicator and remove any effect of ungetc()
.
Because they may contain variable-length multibyte UTF-8
sequences, text-mode files may only fseek()
to a
well-defined position - either the beginning or end of file, or an
absolute position previously returned by ftell()
.
None
ArgCheck
if an incorrect number of arguments
are specified
TypeCheck
if file is
not a File
, offs is not an
Int
or Long
, or whence
is not an Int
RangeCheck
if whence is not one of
io::SEEK_SET
, io::SEEK_CUR
,
or io::SEEK_END
AccessCheck
if file has been closed
IoCheck
for general I/O subsystem errors
file.fseek(0, io::SEEK_END); // Go to the end-of-file