WRITE(II)                    8/5/73                     WRITE(II)


     write - write on a file


     (write = 4.)

     (file descriptor in r0)

     sys  write; buffer; nbytes

     write(fildes, buffer, nbytes)

     char *buffer;


     A file descriptor is a word returned from a successful open,

     creat or pipe call.

     Buffer is the address of nbytes contiguous bytes  which  are

     written  on  the  output  file.   The  number  of characters

     actually written is returned (in r0).  It should be regarded

     as an error if this is not the same as requested.

     Writes which are multiples of 512 characters long and  begin

     on a 512-byte boundary are more efficient than any others.


     creat(II), open(II), pipe(II)


     The error bit (c-bit) is set on an  error:  bad  descriptor,

     buffer  address,  or  count; physical I/O errors.  From C, a

     returned value of -1 indicates an error.