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