[fpc-pascal] Cannot write datetime field on sqlite3 database on ARM

[Michael Van Canneyt]

On Tue, 9 Mar 2021, Toru Takubo via fpc-pascal wrote:

>> I don't know what to advise to further investigate the issue, One thing to
>> try would be to test whether normal float arithmetic or date arithmetic 
>> works.
>> If not, then the compiler people will need to give more advice.
>> 
>
> I created a simple test code, and ran on linux-i386 and linux-arm.
> Test on linux-i386 is OK but on linux-arm, I got unexpected values
> "30-12-99" as datetime and "2.12199579096527E-314" as float, which are 
> different
> from values previously set. (except INT and VARCHAR fields)
>
> ---linux-i386--------------------------------------------
> INT, VARCHAR,           DATETIME,           DOUBLE
> 0, 9-3-21 08:50:23, 9-3-21 08:50:23, 0
> 1, 9-3-21 12:16:06, 9-3-21 12:16:06, 0.142857142857143
> 2, 9-3-21 15:41:49, 9-3-21 15:41:49, 0.285714285714286
> 3, 9-3-21 19:07:32, 9-3-21 19:07:32, 0.428571428571429
> 4, 9-3-21 22:33:15, 9-3-21 22:33:15, 0.571428571428571
> 5, 10-3-21 01:58:58, 10-3-21 01:58:58, 0.714285714285714
> 6, 10-3-21 05:24:40, 10-3-21 05:24:40, 0.857142857142857
> 7, 10-3-21 08:50:23, 10-3-21 08:50:23, 1
> 8, 10-3-21 12:16:06, 10-3-21 12:16:06, 1.14285714285714
> 9, 10-3-21 15:41:49, 10-3-21 15:41:49, 1.28571428571429
>
> ---linux-arm---------------------------------------------
> INT, VARCHAR,           DATETIME,           DOUBLE
> 0, 9-3-21 08:55:53, 30-12-99, 2.12199579096527E-314
> 1, 9-3-21 12:21:36, 30-12-99, 2.12199579096527E-314
> 2, 9-3-21 15:47:18, 30-12-99, 2.12199579096527E-314
> 3, 9-3-21 19:13:01, 30-12-99, 2.12199579096527E-314
> 4, 9-3-21 22:38:44, 30-12-99, 2.12199579096527E-314
> 5, 10-3-21 02:04:27, 30-12-99, 2.12199579096527E-314
> 6, 10-3-21 05:30:10, 30-12-99, 2.12199579096527E-314
> 7, 10-3-21 08:55:53, 30-12-99, 2.12199579096527E-314
> 8, 10-3-21 12:21:36, 30-12-99, 2.12199579096527E-314
> 9, 10-3-21 15:47:19, 30-12-99, 2.12199579096527E-314

thank you for the test program. I tested on linux 64-bit, that works OK too.

When you look in the database on the arm machine  with an sqlite tool, do
you see the correct values or are the inserted values wrong ?

(I'm trying to establish whether the problem happens during read  or write)

>
> I used a shared library libsqlite3.so included in the "DB Browser for 
> SQLite",
> so it should work. What can cause such a problem only in the specific field
> on the specific platform?

Seems like either a floating point issue, or an alignment issue.
I know ARM has some specific behaviour with regard to alignment.

Unfortunately, I have no idea what to test or the means to test it.
Someone more familiar with ARM will need ro test.

Michael.