| Title: | Alpha Developer Support |
| Notice: | [email protected], 800-332-4786 |
| Moderator: | HYDRA::SYSTEM |
| Created: | Mon Jun 06 1994 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 3722 |
| Total number of notes: | 11359 |
Company Name : TIBCO
Contact Name : Taihsing Cha
Phone : (415) 846-5067
Fax :
Email : "[email protected]"
Date/Time in : 17-MAR-1997 17:44
Originally entered by : SWIERKOWSKI
SPE center : PAG
Category : OpenVMS Alpha
OS Version : V6.2
System H/W : AlphaStation 400 4/233
Brief Description of Problem:
-----------------------------
Called re: file access from a "C" program. The program reads a file that is
written to by another process. The second process only reads records present
in the file at the time it opens it and does not pick up new records subsequent-
ly written by the first process.
I'm just guessing that he has got his "sharing" attributes wrong upon the
file open. If this is OpenVMS/RMS, you tell RMS two things: the access you
want (i.e. Read-Only or Read/Write) and the access you want others to have.
By default, when you open a file (in most languages) the "SHR" bits are all
clear (i.e. no sharing with a subsequent process that tries to open the same
file). A second process that comes along and tries to open the file already
opened by the first process is at best going to open a new version of the
file (which of course hasn't been written to). The other possibility is to let
the second process cycle through an close/open cycle each time it wnts to pick
up the new EOF. I'll research this and get back to him, cheers...
Tony Swierkowski
Digital Equipment Corporation
Software Partner Engineering
Palo Alto, California
(415) 617-3601
"[email protected]"
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 3336.1 | Disconnect/Connect cycle to pick up new EOF?... | AMCUCS::SWIERKOWSKI | Quot homines tot sententiae | Fri Mar 28 1997 16:56 | 20 |
Greetings! I've starting researching this and I don't believe there is any inherent bug in RMS that prevents file sharing in general and/or correctly updating the EOF marker when the first process (which writes records) continues to do so after the second process (which reads records) opens the file. Having said that, multiple notes here & there suggest that the application may have to cycle through a disconnect/connect sequence to pick up the updated EOF however. I'm not aware of a more "elegant" solution and I still have some questions about the DEC C RTL vs calling RMS Services directly. I've crafted a message to Taihsing with some basic questions and await feedback... Tony Swierkowski Digital Equipment Corporation Software Partner Engineering Palo Alto, California (415) 617-3601 "[email protected]" | |||||
| 3336.2 | Call closed... | AMCUCS::SWIERKOWSKI | Quot homines tot sententiae | Wed Apr 09 1997 13:21 | 14 |
Greetings! After more email tag back and forth with Tai-Hsing, he seems happy with the solution I presented him with, call closed... Tony Swierkowski Digital Equipment Corporation Software Partner Engineering Palo Alto, California (415) 617-3601 "[email protected]" | |||||