Received: from sss.sss.pgh.pa.us (sss.pgh.pa.us [206.210.65.6]) by hub.org (8.9.2/8.9.1) with ESMTP id KAA48331 for ; Tue, 9 Mar 1999 10:10:23 -0500 (EST) (envelope-from tgl@sss.pgh.pa.us) Received: from sss.sss.pgh.pa.us (localhost [127.0.0.1]) by sss.sss.pgh.pa.us (8.9.1/8.9.1) with ESMTP id KAA11999; Tue, 9 Mar 1999 10:08:57 -0500 (EST) To: Bartek Teodorczyk cc: pgsql-interfaces@postgreSQL.org Subject: Re: [INTERFACES] Getting field length in libpq In-reply-to: Your message of Tue, 09 Mar 1999 15:44:57 +0100 <36E533E9.B72B4C64@it.pl> Date: Tue, 09 Mar 1999 10:08:57 -0500 Message-ID: <11997.920992137@sss.pgh.pa.us> From: Tom Lane Bartek Teodorczyk writes: > I need to get the length of field after executing query. For INT4 fields > it is simple (call PQfsize and get 4) but when I have VARCHAR(30) field > PQfsize returns -1. I cannot call PQgetlength for example first tuple > because this tuple can have 10 chars and PQgetlength returns 10 but I > need 30. Have you any solutions? I believe PQfmod will give you the number you want, for the specific case of char and varchar fields. The meaning of PQfmod is by definition type-specific, so there's no guarantee that it will contain the maximum field width for other data types. For that matter, there's no guarantee that a VARLENA data type even *has* an identifiable maximum width --- the handiest example of one that does not is text. If I were you I'd check PQftype before assuming that I knew what PQfmod means. BTW, keep in mind that PQfsize is the stored size of a datum, but unless you are using binary cursors it has nothing to do with the length of the ASCII representation of the value... regards, tom lane