putc(3) - Unix First Edition Manual Page
11/3/71PUTC, PUTW,

NAME putc, putw, fcreat, flush -- buffered output
SYNOPSIS may $filename , r0jsr r5,fcreat; iobuf

(get byte in r0)jsr r5,putc; iobuf (get word in r0)jsr r5,putw; iobuf

jsr r5,flush; iobuf
DESCRIPTION fcreat creates the given file (mode 17) and sets up the bufferiohuf (size 134(10) bytes); putc and putw write a byte or word

respectively onto the file; flush forces the contents of thebuffer to be written, but does not close the file. The format of the buffer is:

iobuf: .=.+2 / file descriptor.=.+2 / characters unused in buffer

.=.+ 2 / ptr to next free character.=.+128. / buffer

fcreat sets the error bit (c--bit) if the file creation failed;none of the other routines return error information. Before terminating, a program should call flush to force outthe last of the output. The user must supply iohuf, which should begin on a wordboundary.
FILES kept in/etc/liba.a
SEE_ALSO sys creat; sys write; getc, getw, fopen
DIAGNOSTICS error bit possible on fcreat call
BUGS buffers should be changed to 512 bytes.