lseek — move read/write file pointer; seek
off_t lseek(int fildes, off_t offset, int whence);
sets the file pointer associated with the file descriptor as follows:
the pointer is set to
the pointer is set to its current location plus
the pointer is set to the size of the file plus
These symbolic constants are defined in
completes successfully, it returns an integer,
which is the resulting file offset
as measured in bytes from the beginning of the file.
Otherwise, a value of
is returned and
is set to indicate the error.
For all files that are not character or block special files,
the integer returned on successful completion is non-negative.
For character or block special files
that correspond to disk sections larger than 2 gigabytes,
a non-negative integer is returned
for successful seeks beyond 2 gigabytes.
This value is the resulting file offset
as measured in bytes from the beginning of the file,
when taken as an unsigned value.
always indicates an error return,
even when encountered on greater than 2 gigabyte disk sections.
call succeeds for NFS directories even if the resulting
file offset becomes negative.
fails and the file offset remains unchanged
if one or more of the following is true:
is not an open file descriptor.
is associated with a pipe, socket, or
is not one of the supported values.
The resulting file offset would be negative.
The resulting file
would be a value which cannot be represented correctly in an object
Some devices are incapable of seeking.
The value of the file offset associated with such a device is undefined.
on device special files is not supported and the results are not defined.
lseek(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1