Re: [9fans] non-truncating create
Of tertiary interest: Is there a general use for a library function complain() that behaves identically to sysfatal(2) except for not terminating the program? Probably not. The interesting part of sysfatal is the terminating the program, not the printing of the error. Got it. Complain() goes into my private library, together with emalloc co. from back in June... ☺ --Joel
Re: [9fans] non-truncating create
Rc just tries the open, and if that fails, tries the create.
It doesn't even bother looking at the error code.
If the open failed due to permissions, so will the create.
Drawterm barfed on me and I lost the bit of code this suggested; when
I tried to recreate it I ended up checking for OTRUNC a few times.
Not pretty.
Or use create with OEXCL if you really care.
Sort of the way create(2) calls create(5) first, then open(5) if that
failed? My code now looks like:
o = create(oname, omode|OEXCL, ~0); /* fails if file exists */
if(o 0)
o = open(oname, omode);
if(o 0){
complain(can’t open %s for writing: %r, oname);
return;
}
which has no special-case code depending on OTRUNC being set or no.
I suppose I ought to look at /sys/src/cmd/rc to see how it’s really
done. Mañana.
Thanks for the assist.
--Joel
[9fans] SPF implementation
HelloI saw on Wiki TODO a request to implement SPF antispam thing.If there is nobody alreading doing this, i will start it.slds.gabi
Re: [9fans] non-truncating create
Rc says something like:
if ((fd = open(file, OWRITE)) 0 (fd = create(file, OWRITE, 0666)) 0) {
complain(...);
return;
}
seek(fd, 0, 2);
You don't really mean ~0 as the argument to create.
Russ
On 10/9/06, Joel chesky Salomon [EMAIL PROTECTED] wrote:
Rc just tries the open, and if that fails, tries the create.
It doesn't even bother looking at the error code.
If the open failed due to permissions, so will the create.
Drawterm barfed on me and I lost the bit of code this suggested; when
I tried to recreate it I ended up checking for OTRUNC a few times.
Not pretty.
Or use create with OEXCL if you really care.
Sort of the way create(2) calls create(5) first, then open(5) if that
failed? My code now looks like:
o = create(oname, omode|OEXCL, ~0); /* fails if file exists */
if(o 0)
o = open(oname, omode);
if(o 0){
complain(can't open %s for writing: %r, oname);
return;
}
which has no special-case code depending on OTRUNC being set or no.
I suppose I ought to look at /sys/src/cmd/rc to see how it's really
done. Mañana.
Thanks for the assist.
--Joel
Re: [9fans] scuzz doesn't like CD-RW?
Are you using CD-R or CD-RW media? Have you tried scuzz -r /dev/sdD0? I've just hooked up a CD-R drive so I'll verify that that still works.
[9fans] Plan 9 in robotics
Hi everyone Is anyone currently using Plan 9 to control robots? It seems to me that the O.S. is well-suited for interfacing with some of the devices my robotics club uses (serial GPS, etc), and the networked aspect would make it useful for communicating among distributed, one-function modules (we are considering ARM processors for this). Thanks John Floren -- Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn
Re: [9fans] Plan 9 in robotics
Is anyone currently using Plan 9 to control robots? like styx-on-a-brick? http://www.vitanuova.com/inferno/rcx_paper.html
Re: [9fans] non-truncating create
And if you are interested in a much deeper discussion, look at the archives
from 1999.
-Original Message-
From: Russ Cox [mailto:[EMAIL PROTECTED]
Sent: Monday, October 9, 2006 10:57 AM
To: 'Fans of the OS Plan 9 from Bell Labs'
Subject: Re: [9fans] non-truncating create
Rc says something like:
if ((fd = open(file, OWRITE)) 0 (fd = create(file, OWRITE, 0666)) 0) {
complain(...);
return;
}
seek(fd, 0, 2);
You don't really mean ~0 as the argument to create.
Russ
On 10/9/06, Joel chesky Salomon [EMAIL PROTECTED] wrote:
Rc just tries the open, and if that fails, tries the create.
It doesn't even bother looking at the error code.
If the open failed due to permissions, so will the create.
Drawterm barfed on me and I lost the bit of code this suggested; when
I tried to recreate it I ended up checking for OTRUNC a few times.
Not pretty.
Or use create with OEXCL if you really care.
Sort of the way create(2) calls create(5) first, then open(5) if that
failed? My code now looks like:
o = create(oname, omode|OEXCL, ~0); /* fails if file exists */
if(o 0)
o = open(oname, omode);
if(o 0){
complain(can't open %s for writing: %r, oname);
return;
}
which has no special-case code depending on OTRUNC being set or no.
I suppose I ought to look at /sys/src/cmd/rc to see how it's really
done. Mañana.
Thanks for the assist.
--Joel
Re: [9fans] non-truncating create
On 10/9/06, G. David Butler [EMAIL PROTECTED] wrote: And if you are interested in a much deeper discussion, look at the archives from 1999. Looking at the subject headers at http://9fans.net/archive/1999, I'm not seeing anything directly related to open or create. Could you please be a bit more specific? --Joel
Re: [9fans] non-truncating create
And if you are interested in a much deeper discussion, look at the archives from 1999. Actually it was 1998: http://9fans.net/archive/1998/02 especially http://9fans.net/archive/1998/02/17 We explicitly considered this when working on 9P2000 and added the OEXCL flag to create to address this problem. Russ
Re: [9fans] pages in nroff
Unix manpages these days are formatted for online viewing just as you suggest, and it seems to work fine. e.g. linux does: (echo .ll 10.6i; echo .pl 1100i; /usr/bin/gunzip -c '/usr/share/man/man1/date.1.gz'; echo; echo .pl \n(nlu+10 ) | /usr/bin/gtbl | /usr/bin/nroff -c -mandoc | /usr/bin/less -isr
RE: [9fans] scuzz doesn't like CD-RW?
I can also burn ISO CD-RW on plan9 with that drive, I forgot to mention it. The problem is that I can§t burn a tar file directly, i.e., without cdfs, so I could read it thus: tar tvf /dev/sdD0/data aftr blanking the cd, I got rid of that 'bus timeout' message, probe ready inquiry rewind all work, but I still can't write My problem is that I don't trust ISO-9660 and companion very much. writing .tar instead of .iso using cdfs would probably work, but would force me to use the cdfs overhead. Reasoning is that if something goes wrong, I can get most of the data back from tar, not so from iso. Thanks for the response, best regards, ++pac -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Monday, October 09, 2006 8:34 PM To: 9fans@cse.psu.edu Subject: Re: [9fans] scuzz doesn't like CD-RW? I just burned a CD-R using a SCSI drive and cdfs. I don't think I normally use scuzz to talk to CD drives, but scuzz -r /dev/sd11 ready inquiry works.
