/sys/doc/ Documentation archive

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, dup, or pipe call.

     Buffer is the address of nbytes contiguous bytes  which  are
     written  on the output file.  The number of characters actu-
     ally 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 in the file 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.

                              - 1 -