term% cat index.txt LSEEK(2) System Calls Manual LSEEK(2)
NAME
lseek, tell - move read/write pointer
SYNOPSIS
long lseek(fildes, offset, whence)
long offset;
long tell(fildes)
DESCRIPTION
The file descriptor refers to a file open for reading or writing. The
read (resp. write) pointer for the file is set as follows:
If whence is 0, the pointer is set to offset bytes.
If whence is 1, the pointer is set to its current location plus
offset.
If whence is 2, the pointer is set to the size of the file plus
offset.
The returned value is the resulting pointer location.
The obsolete function tell(fildes) is identical to lseek(fildes, 0L, 1
).
Seeking far beyond the end of a file, then writing, creates a gap or
`hole', which occupies no physical space and reads as zeros.
SEE ALSO
open(2), creat(2), fseek(3)
DIAGNOSTICS
-1 is returned for an undefined file descriptor, seek on a pipe, or
seek to a position before the beginning of file.
BUGS
Lseek is a no-op on character special files.
LSEEK(2)