On Nov 4, 2009, at 4:53 AM, Alexander Drozd wrote:
>
>  My name is Alexander. I am working on an open-source  spaced- 
> repetition software project  (http://code.google.com/p/pbanki/). My  
> software relies on SQLite library. I came across some bug-like  
> problems with running SQLite on a low-memory e-ink reader device. I  
> am very  sorry to bother you, but I tried to submit my  problem to  
> the bugtracker at the SQLite site, and for some reason anonymous  
> login failed.
>
>  The problem appears at the point of reading real values from an   
> SQLite database. I created a simple database
>
> CREATE TABLE cards (
>    text TEXT NOT NULL,
>    value REAL NOT NULL
> );
>
> I also tried to use NUMERIC and FLOAT instead of REAL. Then I  
> inserted a few values:
>
> INSERT INTO cards VALUES('second',100.1);
> INSERT INTO cards VALUES('first', 100.0);
>
> Then I execute "select * from cards order by due" query with sample  
> code from http://www.sqlite.org/quickstart.html It works perfectly  
> when compiled on desktop computer, but fails on target device. The  
> device is PocketBook301+ (http://pocketbook.com.ua/). Unfortunately  
> their site does not have an English version. This device is based on  
> Samsung S3C2440 AL-40 CPU. It runs under open-source firmware called  
> pocketbookfree, that is based on Linux 2.6.18.2 armv4tl.
>
> The above query run on pocketbook returns corrupted values for  
> floats if they have a non-zero fractional part:
>
> text = first
> val = 100.0
>
> text = second
> val = 1.90359837350824e+185
>
> Sorting by columns containing float numbers also fails when  
> specified with ORDER BY. I am not sure whether this is an issue with  
> SQLite or with cross-compiler for PocketBook, but I would greatly  
> appreciate any suggestions on how to treat this problem.


I'm guessing that your hardward does not implement IEEE 754 floating  
point correctly.  We've seen that sort of thing before, especially  
with GCC.  There are some options to GCC (which escape my memory right  
now) that can force it to use strict IEEE 754 floating point rather  
than its preferred, speedier but non-standard alternative.


D. Richard Hipp
d...@hwaci.com



_______________________________________________
sqlite-users mailing list
sqlite-users@sqlite.org
http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users

Reply via email to