11/3/71 GETC, GETW, FOPEN (III)





11/3/71                                   GETC, GETW, FOPEN (III)





NAME            getw, getc, fopen  --  buffered input



SYNOPSIS        mov     $filename,r0

                jsr     r5,fopen; iobuf



                jsr     r5,getc; iobuf

                (character in r0)



                jsr     r5,getw; iobuf

                (word in r0)



DESCRIPTION     These routines are used to provide a buffered in-

                put facility.  iobuf is the address of a 134(10)

                byte buffer area whose contents are maintained by

                these routines.  Its format is:



                ioptr:  .=.+2           / file descriptor

                        .=.+2           / characters left in buffer

                        .=.+2           / ptr to next character

                        .=.+128.        / the buffer



                fopen should be called initially to open the

                file.  On return, the error bit (c-bit) is set if

                the open failed.  If fopen is never called, get

                will read from the standard input file.



                getc returns the next byte from the file in r0.

                The error bit is set on end of file or a read er-

                ror.



                getw returns the next word in r0.  getc and getw

                may be used alternately; there are no odd/even

                problems.



                iobuf must be provided by the user; it must be on

                a word boundary.



FILES           kept in /etc/liba.a



SEE ALSO        sys open, sys read; putc, putw, fcreat



DIAGNOSTICS     c-bit set on EOF or error



BUGS            for greater speed, the buffer should be 512 bytes

                long.  Unfortunately, this will cause several ex-

                isting programs to stop working.



OWNER           dmr
squoze.net
