Chapter 17. Communicating with a PostScript Printer

	Example	Relevant Functions
17.1	printer/lprps.h Header file: all internal interfaces of lprps.	See below
17.2	printer/vars.c lprps global variable declarations	none
17.3	printer/main.c main program: process options, send file to the printer, do accounting, send errors from PS interpreter back to user	log_open (Stevens' lib), log_msg (Stevens' lib), log_sys (Stevens' lib), tty_open, get_status, get_page, send_file, do_acct, getopt, atexit, exit
17.4	printer/acct.c Write number of printed pages, hostname and username into accounting file	log_sys (Stevens' lib), fopen, fprintf, fclose
17.5	printer/tty.c Terminal functions: set_block, set_nonblock, block_write, tty_flush, tty_open	log_sys (Stevens' lib), fcntl write open, tcflush, tcgetattr, tcsetattr, cfsetispeed, cfsetospeed,
17.6	printer/interrupt.c Interrupt signal handling: sig_int, handle_intr, set_intr, clear_intr	log_sys (Stevens' lib), signal, exit, set_alrm, clear_alrm, tty_flush, block_write, proc_upto_eof, get_page, do_acct, signal_intr
17.7	printer/alarm.c Timeouts handling: sig_alrm, handle_alrm, set_alrm, clear_alrm	log_ret (Stevens' lib), log_sys (Stevens' lib), alarm, sleep, exit, signal_intr, signal
17.8	printer/getstatus.c Check status of printer before sending job	set_alrm, clear_alrm, tty_flush, block_write, init_input, proc_some_input, sleep, exit
17.9	printer/pagecount.c Fetch the printer's page count by sending the appropriate PostScript program to the printer	set_alrm, clear_alrm, tty_flush, block_write, init_input, proc_some_input, proc_upto_eof
17.10	printer/sendfile.c Send a file to the printer. Called by main, to copy stdin to printer	init_input, set_intr, getchar, out_char, block_write, proc_upto_eof
17.11	printer/mail.c send any output that is not a status message from the PS interpreter, by mail to user	log_sys (Stevens' lib), fputs, putc, fprintf, fopen, fclose, sprintf, system, unlink
17.12	printer/output.c Implements out_char which outputs a single char to the printer but without blocking, and while dealing with input from the printer. Called in a tight loop by send_file	FD_ZERO, FD_SET, FD_ISSET, select, read, write, log_sys (Stevens' lib), set_nonblock, handle_intr, proc_input_char
17.13	printer/input.c Read and process all input from the printer init_input, proc_upto_eof, proc_some_input, proc_input_char	log_sys (Stevens' lib), FD_ZERO, FD_SET, select, read, set_nonblock, handle_intr, handle_alrm, mail_char, msg_init, msg_char, abort
17.14	printer/message.c Process messages returned from the printer (at the low level). msg_init, msg_char, proc_msg, printer_flushing	log_msg (Stevens' lib), strtok, isspace, strchr, strcmp, sscanf, exit, mail_line, clear_intr, tty_flush, block_write, proc_upto_eof get_page, do_acct