Sorry about this, but I really can't work out what's going on here, and
could do with some clues.

The basic problem is that I'm getting string values of columns into PHP
padded on the right to four times their correct length.

I've tried various combinations of things and got various weird results.
Here's one example:

(1) I believe the database default character set is UTF8 (although I
don't know in detail what that means or what it's used for)

SQL> select rdb$character_set_name from rdb$database;
RDB$CHARACTER_SET_NAME
UTF8

(2) I've got a column in a table defined as ASCII (not that that makes
an awful lot of difference, I get very similar results if it's UTF8):

METERID CHAR( 8) CHARACTER SET ASCII
COLLATE ASCII,

(3) I connect ISQL without a -ch command line parameter and get the
field arriving in ISQL as eight characters long:

SQL> select meterid from tblmeterchange;

METERID
========
0001A6BN
0001A6BN

(4) I connect ISQL with -ch UTF8 and get the field arriving in ISQL as
32 characters long:

SQL> select meterid from tblmeterchange;

METERID
================================
0001A6BN
0001A6BN

(5) I connect via PHP using ibase_connect with "UTF8" as the character
set parameter and get this eight character field returned as the eight
wanted characters padded on the right with 24 spaces.

(6) If I change the definition of the METERID column to UTF8 I similarly
get 32 characters in PHP.

So what should I be doing to get an eight character value of an eight
character field turning up as eight characters in PHP? (I don't think I
have the option of setting the connection charset to anything other than
UTF8 because I don't know what else it might affect and there are plenty
of other columns in the database which, unlike this one, can't be
declared as ASCII ... but then I don't know exactly what the concept of
"connection character set" means or does anyway.)

I have read
http://www.firebirdsql.org/file/community/ppts/fbcon11/FbCon2011-Charsets-Heymann.pdf,
but that doesn't help - it suggests that Firebird will transliterate as
necessary, but padding an eight character string with 24 spaces to make
a 32 character string isn't any sort of "transliteration" I'm familiar with.

--
Tim Ward