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Date: Sun, 5 Apr 1998 14:03:39 +0300
To: Tom Good <tomg@nrnet.org>
From: Herouth Maoz <herouth@oumail.openu.ac.il>
Subject: Re: [INTERFACES] ecpg - `exec sql delete' failing
Cc: PostgreSQL Interfaces List <pgsql-interfaces@postgreSQL.org>

At 0:46 +0300 on 4/4/98, Tom Good wrote:


> Hi.  Can't fathom why this code precompiles, compiles, links and
> seems to execute - but won't delete records.
> As always - any assistance greatly appreciated!
> Tom
> --- pgc code follows ---
>
> #include <stdio.h>
>
> EXEC SQL BEGIN DECLARE SECTION;
>   int ClientID;         /* client_id */
>   char FirstName[16];   /* client_fname */
>   char LastName[16];    /* client_lname */
>   char NameTag[16];     /* usr buffer */
>   char reply;           /* usr buffer */
>   int delete_num;       /* usr buffer */
> EXEC SQL END DECLARE SECTION;

[snip]

> printf("\t\tRemove this record (y/n): ");
> scanf("%s", &reply);
> if(reply == 'y') {
> printf("\t\tEnter Client ID Number: ");
> scanf("%d", &delete_num);
> EXEC SQL DELETE FROM central WHERE client_id = delete_num;
> }
> else printf("Exiting...record not removed.\n");
>   exit(0);
> }

Reminds me of a mistake a friend of mine did in one of his university
exercises. The variable reply is declared as char, but you're scanning to
it as string, so there is a "\0" which enters somewhere (perhaps the
alignment bytes of delete_num, who knows), and causes a garble. Why don't
you try to scan it using "%c", not "%s"?

Herouth

--
Herouth Maoz, B.Sc.                Work:      herouth@oumail.openu.ac.il
                                   Home:       herutma@telem.openu.ac.il
HOME PAGE:                            http://homes.openu.ac.il/~herouth/
Internet technical assistant              Open University, Telem Project