lseek(2)                         UNIX System V                         lseek(2)


NAME
      lseek - move read/write file pointer

SYNOPSIS
      #include <sys/types.h>
      #include <unistd.h>

      offt lseek (int fildes, offt offset, int whence);

DESCRIPTION
      fildes is a file descriptor returned from a creat, open, dup, fcntl,
      pipe, or ioctl system call.  lseek sets the file pointer associated with
      fildes as follows:

            If whence is SEEKSET, the pointer is set to offset bytes.

            If whence is SEEKCUR, the pointer is set to its current location
                  plus offset.

            If whence is SEEKEND, the pointer is set to the size of the file
                  plus offset.

      On success, lseek returns the resulting pointer location, as measured in
      bytes from the beginning of the file.  Note that if fildes is a remote
      file descriptor and offset is negative, lseek returns the file pointer
      even if it is negative.

      lseek allows the file pointer to be set beyond the existing data in the
      file. If data are later written at this point, subsequent reads in the
      gap between the previous end of data and the newly written data will
      return bytes of value 0 until data are written into the gap.

      lseek fails and the file pointer remains unchanged if one or more of the
      following are true:

      EBADF          fildes is not an open file descriptor.

      ESPIPE         fildes is associated with a pipe or fifo.

      EINVAL         whence is not SEEKSET, SEEKCUR, or SEEKEND.  The
                     process also gets a SIGSYS signal.

      EINVAL         fildes is not a remote file descriptor, and the resulting
                     file pointer would be negative.

      Some devices are incapable of seeking.  The value of the file pointer
      associated with such a device is undefined.

SEE ALSO
      creat(2), dup(2), fcntl(2), open(2).




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lseek(2)                         UNIX System V                         lseek(2)


DIAGNOSTICS
      Upon successful completion, a non-negative integer indicating the file
      pointer value is returned.  Otherwise, a value of -1 is returned and
      errno is set to indicate the error.


















































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