Re: Null Characters in Strings, Version 9.3.1

On 02/18/2014 09:39 PM, Nils Gösche wrote:
> Heikki wrote:
>
>> On 02/18/2014 07:06 PM, Nils Gösche wrote:
>>> I wrote:
>>>
>>>> If I retrieve the value in a C# program using the ODBC driver, I get
>>>> a string that has a null character at position 459, but a total
>>>> length of 487! The string up to position 458 is correct, but has
>> now
>>>> been extended with a null character and a few junk characters.
>>>
>>> Am I the only one thinking this is a serious bug?
>>
>> Maybe.. I don't have a C# environment to test this with; if you can
>> write a small stand-alone C program to reproduce this and post it, I'll
>> take a look.
>
> Thanks! I have never written an ODBC program in C before. Wow, what a PITA... ;-).

Yep, it's quite verbose :-).

> I took a little example program from Microsoft's site and adapted it. The code is attached.

I'm afraid I can't easily compile and execute that either, with all the
Windows-ism's in it. Could you pick one of the regression test cases
(e.g
http://git.postgresql.org/gitweb/?p=psqlodbc.git;a=blob_plain;f=test/src/select-test.c;hb=HEAD),
and modify it to reproduce the problem? And please also include the SQL
statements to create the test table and data.

> The essential point is at line 353:
>
> if (wcslen(pThisBinding->wszBuffer) * sizeof(wchar_t) != pThisBinding->indPtr)
> {
> wprintf(L"2 * wcslen = %d, indPtr = %d\n", wcslen(pThisBinding->wszBuffer) * sizeof(wchar_t),
> pThisBinding->indPtr);
> }
> else
> {
> wprintf(pThisBinding->fChar ? DISPLAY_FORMAT_C:DISPLAY_FORMAT,
> PIPE,
> pThisBinding->cDisplaySize,
> pThisBinding->cDisplaySize,
> pThisBinding->wszBuffer);
> }
>
> If I run this with version 9.2.1 of the driver (I am using 32 Bit here), it will go to the else clause and print the value of the text column. However, if I run this with the latest version, I get the following output:

Hmm. If you could pinpoint it to the exact commit that changed the
behavior, that would help too.

- Heikki