tombre@crin.UUCP (Karl Tombre) (11/20/86)
We are running several versions of UNIX on different machines. One of them
is Berkeley 4.2, on a VAX 11/785. We also have some SM90 machines under SMX
5.1, which is supposed to be System 5 compatible.
As we wanted to port some programs from the VAX to the SM90, we got trouble
with a system function called select. It is found in 4.2 but not in SMX.
Looking in the sources of 4.2, I only find some assembler stuff and no C
program.
So my questions are ?
1) What is select for?
2) Does it exist for system V?
3) If not, which function is the equivalent, if any?
Please mail the answer. Many thanks,
--
--- Karl Tombre @ CRIN (Centre de Recherche en Informatique de Nancy)
UUCP: ...!mcvax!inria!crin!tombre EUROKOM: Karl Tombre CRIN
POST: Karl Tombre, CRIN, B.P. 239, 54506 VANDOEUVRE CEDEX, France
TEL : (+33) 83.91.21.20
"Il n'y a de honte qu'a` n'en point avoir" - Blaise Pascalmark@adec23.UUCP (Mark Salyzyn) (03/02/89)
I have a UNIX V5 like system. No select(2) call. I would like to ask the net if there is a select(2) man page available so that I can implement the call `correctly'. I may implement it in the kernel or as a subset library routine, this will be decided when I see the full definition of select. please e-mail me if you have it (and are willing to send it :-} ) and I will get back to you if you are the closest machine. Thanks in advance, Ciao, -- Mark Salyzyn @ alberta!(edm,ncc,uofaee)!adec23!mark or dragos!adec23!mark
jeff@questar.QUESTAR.MN.ORG (Jeff Holmes) (01/11/90)
Could someone who understands the select() system call better than I do tell me... if there is any way to get select() to tell me HOW MANY characters there are in the buffer that are waiting to be read, similar to using FIONREAD with ioctl() under BSD? Thank you, Jeff -- Jeff Holmes DOMAIN: jeff@questar.mn.org Questar Data Systems UUCP: amdahl!bungia!questar!jeff St. Paul, MN 55121 AT&T: +1 612 688 0089
ssj@castle.ed.ac.uk (S Johal) (02/02/90)
I have an application that is event driven. I use select (- actually
I use XtAddInput form X Toolkit Intrinsics stuff). That tells me if
any input has arrived. I then use stdio.h gear to read from the
descriptor.
I read 'units' of information using stdio, the number of units arriving
being an unknown integer number. My problem is that I could not find any
stdio function that would do the equivilant of select - ie. as sort of
"is there any more data left to be read ? - without actually reading it".
So, what I did was look at stdio.h, and decided to use FILE->_cnt, to
tell me if there are any items left in the buffer pool.
The questions I need help with, are:
(1) Is it *totally* portable/POSIX compatible to use _cnt ?
(2) if not, Have I missed something in stdio.h that will let me
do what I'm after ?
*-------------------------------------------*----------------------------*
* Subindrao Johal, *++++++++++++++++++++++++++++*
* SARI Project, * tel: 031 668 1550 x219 *
* Department of Electrical Engineering, * fax: 031 662 4678 *
* University of Edinburgh, * email: ssj@sari.ed.ac.uk *
* The King's Buildings, Edinburgh EH9 3JL *++++++++++++++++++++++++++++*
*-------------------------------------------*----------------------------*chris@mimsy.umd.edu (Chris Torek) (02/03/90)
In article <1988@castle.ed.ac.uk> ssj@castle.ed.ac.uk (S Johal) writes: > (1) Is it *totally* portable/POSIX compatible to use _cnt ? No: there is no guarantee that a `FILE *' can be followed to a `_cnt' field, and in my stdio, there is no _cnt field. (There are two called _r and _w that, collectively, mean what _cnt used to.) > (2) if not, Have I missed something in stdio.h that will let me > do what I'm after ? No. stdio has no multiplexing feature analagous to select(). If you need select(), you cannot use stdio; if you need stdio, you cannot use select(). If absolutely necessary, you are probably best off by defining a small system-dependent module to do what select does but on multiple FILE objects. -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 7163) Domain: chris@cs.umd.edu Path: uunet!mimsy!chris
field@cs.pitt.edu (Gus) (08/07/90)
I using select () to detect data on a file descriptor. Upon detecting info, I perform a read (). If I don't read all the data on the descriptor, and then return to select (), select will only return when _new_ data is delivered to the descriptor. Is there a way to have select () return whenever there is pending data to be read (whether or not new data has arrived). Some specifics: I'm running on a Sun-4, 4.0.3. The file I'm reading from is a serial port (canonical off, c_cc[MIN] = 1, c_cc[TIME] = 0, no echo). I would like to avoid performing a manual select (ioctl with FIONREAD) since I may be listening to lots of serial ports. Please respond via e-mail, I'll summarize if there is interest. Brian ----- field@cs.pitt.edu
dnb@meshugge.media.mit.edu (David N. Blank) (09/28/90)
>Has anyone out there ported this program to the SysV or Xenix >environment? ( it uses the BSD select() call) Let me ask a more general question: what's the SysV version of/ replacement paradigm for select()? Thanks. Peace, dNb
thomas@uppsala.telesoft.se (Thomas Tornblom) (10/01/90)
In article <DNB.90Sep28101809@meshugge.media.mit.edu> dnb@meshugge.media.mit.edu (David N. Blank) writes: >Has anyone out there ported this program to the SysV or Xenix >environment? ( it uses the BSD select() call) Let me ask a more general question: what's the SysV version of/ replacement paradigm for select()? Thanks. Peace, dNb poll(2) if sysV.x & x >= 3. Thomas -- Real life: Thomas Tornblom Email: thomas@uppsala.telesoft.se Snail mail: Telesoft Uppsala AB Phone: +46 18 189406 Box 1218 Fax: +46 18 132039 S - 751 42 Uppsala, Sweden
hascall@cs.iastate.edu (10/28/90)
after a:
select( ..., exceptfds, ...)
how do I find out what kind of exception has occurred on
the socket(s) indicated in exceptfds? Heck, what *are*
the possible exception conditions? closed? out-of-band data?
urgent data? others?
many thanks,
John Hascall / john@iastate.edu / hascall@atanasoff.cs.iastate.edu