NewLC - Faulty [] operator on TBuf in 3rd Edition - Comments

Re: Faulty [] operator on TBuf in 3rd Edition

euroq — Thu, 04 Jan 2007 21:19:14 +0100

Whooooops!

I stand corrected. It never worked on 2nd edition. This whole time I thought that a TBuf was an array. My bad.

It turns out that while stress testing the application something happened which never happened in the 2nd edition.

-euroq

Re: Faulty [] operator on TBuf in 3rd Edition

fig7 — Wed, 03 Jan 2007 21:13:44 +0100

TBuf<32> buf;
buf[0] = 'A'; // will cause USER 9 because buf's length is 0

I'd be very surprised if this code behaves differently on S60 second edition. The behaviour here was determined a very long time ago (EPOC ER5 and earlier I'm sure)

A newly created TBuf is empty, so it doesn't have any elements to access. It has always been this way. Are you absolutely sure that you are not getting a panic on S60 V2?

Re: Faulty [] operator on TBuf in 3rd Edition

euroq — Wed, 03 Jan 2007 16:38:23 +0100

Actually, aFileName was usually of length 10 or so. The problem is that you simply can't do this:

Code:

TBuf<32> buf;
buf[0] = 'A'; // will cause USER 9 because buf's length is 0

On 2nd edition, that code would work; on 3rd edition, I'm presuming that the operator[] has changed its connotation to be used as an accessor instead of a modifier. For anotherwords, I presume this will work on the 3rd edition:

Code:

TBuf<32> buf;
buf = _L("ABC");
TChar c = buf[0]; // length of buf is 3, so buf[0] works
buf[0] = 'A'; // now this works because length is 3

Re: Faulty [] operator on TBuf in 3rd Edition

vin2ktalks — Wed, 03 Jan 2007 05:43:00 +0100

Quote

USER 9, if anIndex is negative or is greater than or equal to the current length of this descriptor.

Now check your for loop: it's i = 0; i <= strlen(aFileName) so that means in this case 0 - 32, right.

Now see this SDK Help:

Quote

TInt anIndex The position the data item within this descriptor's data. This is an offset value; a zero value refers to the leftmost data position.

So I think anIndex is becoming greater than the current length of this descriptor.

try changing the for loop to: i = 0; i < strlen(aFileName); may work.

Faulty [] operator on TBuf in 3rd Edition

euroq — Tue, 02 Jan 2007 23:50:57 +0100