On Sep 27, 2017, at 10:00 AM, Keith Medcalf <kmedc...@dessus.com> wrote:
> On Wednesday, 27 September, 2017 10:39, Guy Harris <g...@alum.mit.edu> wrote: > >> On Sep 27, 2017, at 6:58 AM, Keith Medcalf <kmedc...@dessus.com> wrote: > >>> Well, the terminology is correct. These *ARE* I/O Errors. The >>> system attempted I/O. It failed. Hence the term I/O Error. > >> Just don't call it a "disk I/O error". > > Well, maybe. However the I/O that had the error was associated with a disk > operation (as opposed to a "Video I/O Error", or a "Cardpunch I/O Error", > "Printer I/O Error", etc.). Actually, if it had occurred on my machine, it wouldn't have been associated with a disk operation; should the application check where the data is stored and say "flash memory I/O" error if appropriate? :-) The point is that the *disk* isn't particularly relevant to some possible errors - the problem isn't with the *disk*, which reported no error, the problem is with something in the *file system*, such as the amount of space available, the permissions on files, etc.. >>> It is irrelevant whether the error was caused because the heads on >>> the tape drive need cleaning, access was denied to spool storage, the >>> disk was full, someone yanked the cable out of the disk drive, or the >>> card reader got jammed up. > >> I.e., SQLITE_IOERR is equivalent to -1 as a return from various UN*X >> system calls, so that, when a program sees it, it needs to get >> further error information, such as an errno value, to deal with the >> error and, if necessary, to report it. > > Yes. An I/O operation of some sort was attempted. That I/O operation > involved some sort of "disk" access. That operation failed with an error. ...and the next step is to determine what the exact error was. >> So it *is* relevant to what to do next. > > Well, in the same sort of way as the message from attempting to send Snail > mail "Mail Undeliverable" is relevant to what to do next. You know that the > error was related to the delivery of the postal item just as the "Disk I/O > Error" indicates that an I/O operation that involved a disk operation failed > with an error. > > In both cases you need to query for the underlying error condition in order > to determine what to do. Well, in the first case, the postal service may well say more than just "Mail undeliverable", such as "no such person at that address", "no such address", etc.. > So in that sense it is relevant to what to do next -- you need to query for > more particulars. This is opposed to say a "Syntax Error" in which it is > pretty clear that the error is a mis-formed statement. Yes, but even in *that* case, it's often possible to say, for example, "there's no operator between the operands "foo" and "bar"" rather than just "syntax error". _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
