SEEK(II)                     3/15/72                     SEEK(II)


     seek - move read/write pointer


     (seek = 19.)

     (file descriptor in r0)

     sys seek; offset; ptrname

     seek(fildes, offset, ptrname)


     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 ptrname is 0, the pointer is set to offset.

        if ptrname is 1,  the  pointer  is  set  to  its  current

           location plus offset.

        if ptrname is 2, the pointer is set to the  size  of  the

           file plus offset.

        if ptrname is 3, 4 or 5, the meaning is as above for 0, 1

           and 2 except that the offset is multiplied by 512.

     If ptrname is 0 or 3, offset is unsigned,  otherwise  it  is



     open(II), creat(II)


     The  error  bit  (c-bit)  is  set  for  an  undefined   file

     descriptor.  From C, a -1 return indicates an error.