matt@iquery.UUCP (Matt Reedy) (09/02/88)
We have a very terminal-I/O intensive application and are attempting to
optimize the output to the terminal. (We looked at curses but decided against
it because we needed more flexibility.) What is the fastest way to get
output to the terminal? We have tried two methods:
write ( 1, line, strlen(line) ); building and writing a line at a time
and
setvbuf (stdout, _IOFBF, buf, 4096 )
fputs (line,stdout) using a very large buffer size
Neither of these seems to be as fast as curses. Someone told me curses is
faster because it doesn't send very many 'locate cursor' ( tgoto (CM..) )
commands. Is this true? Any other ideas?
Thanks in advance.
matt
--
Matthew Reedy UUCP: {harvard!adelie,gatech!petro}!iquery!matt
Programmed Intelligence Corp. "Lots of people without brains do alot of talking"
400 N Loop 1604 E, Suite 330 Scarecrow - "Wizard of Oz"
San Antonio, TX 78232 (512) 490 6684les@chinet.UUCP (Leslie Mikesell) (09/04/88)
In article <136@iquery.UUCP> matt@iquery.UUCP (Matt Reedy) writes: >We have a very terminal-I/O intensive application and are attempting to >optimize the output to the terminal. (We looked at curses but decided against >it because we needed more flexibility.) What is the fastest way to get >output to the terminal? We have tried two methods: .... >Neither of these seems to be as fast as curses. Someone told me curses is >faster because it doesn't send very many 'locate cursor' ( tgoto (CM..) ) >commands. Is this true? Any other ideas? Curses is fast because it doesn't actually output everything you send. It keeps track of what is already on the screen and skips anything that is already there. It also performs calculations to optimize the output depending on the functions available on the particular terminal. You can get an idea of what is happening if your terminal has a "monitor" mode where it displays control sequences instead of obeying them. Depending on what you intend to display, it may be easy or difficult to do this in your own code (probably difficult). Les Mikesell
mkhaw@teknowledge-vaxc.ARPA (Mike Khaw) (09/04/88)
->We have a very terminal-I/O intensive application and are attempting to
->optimize the output to the terminal. (We looked at curses but decided against
->it because we needed more flexibility.) What is the fastest way to get
->output to the terminal? We have tried two methods:
- ....
->Neither of these seems to be as fast as curses. Someone told me curses is
->faster because it doesn't send very many 'locate cursor' ( tgoto (CM..) )
->commands. Is this true? Any other ideas?
-
- Curses is fast because it doesn't actually output everything you send. It
- keeps track of what is already on the screen and skips anything that is
- already there. It also performs calculations to optimize the output
- depending on the functions available on the particular terminal. You
- can get an idea of what is happening if your terminal has a "monitor"
- mode where it displays control sequences instead of obeying them.
I can corroborate the last paragraph above:
I actually had to do something like this on VMS once (no curses!). We
had a terminal-output bound program, so to speed things up, we buffered
up 1 screen-update worth of output before blasting the buffered-up data
to the terminal. It included (I think) internally optimizing cursor
motion commands to minimize the number of bytes sent to the terminal.
It speeded up the application appreciably.
Mike Khaw
--
internet: mkhaw@teknowledge.arpa
uucp: {uunet|sun|ucbvax|decwrl|uw-beaver}!mkhaw%teknowledge.arpa
hardcopy: Teknowledge Inc, 1850 Embarcadero Rd, POB 10119, Palo Alto, CA 94303