Re: ECPG Deallocate PREPARE statement - bug ?

leif(at)crysberg(dot)dk wrote:
> I have a program that I need compile using PostgreSQL
> 8.4.0 (or later) and it must be able to run on an 8.3.5 based
> system as well as 8.4.0. I'm using embedded SQL for C and I
> have the following sequence of statements:
>
> snprintf( stmt, 3000, "SELECT count(*) FROM %s WHERE %s",
> *table, *where );
> EXEC SQL AT :_thisDbConn PREPARE cntstmt FROM :stmt;
> EXEC SQL AT :_thisDbConn EXECUTE cntstmt INTO :recCount :fnull;
> .
> .
> EXEC SQL DEALLOCATE PREPARE cntstmt;
>
> This seems to be ok running on the 8.4.0 system, but when
> running it on the 8.3.5, it complains that it is an 'Invalid
> statement name cntstmt' for the deallocation.
>
> I then tried to add the 'AT :_thisDbConn' to the
> DEALLOCATE statement, but ecpg complained that there was no
> "at" allowed for deallocate. However, looking at the output
> (the .c file) I noticed that it had generated an apparently
> correct ECPG_deallocate() call. Manually compiling this and
> linking the program turned out to be able to run on both the
> 8.3.5 and the 8.4.0 system without problems.
>
> Is this a bug in ecpg or am I doing something wrong ?

I cannot reproduce this.

I used the followind program that is based on your samples:

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char** argv) {
EXEC SQL BEGIN DECLARE SECTION;
char stmt[100], _thisDbConn[] = "mydb";
int fnull, recCount;
EXEC SQL END DECLARE SECTION;
const char table[] = "sometable", where[] = "TRUE";

EXEC SQL WHENEVER SQLWARNING SQLPRINT;
EXEC SQL WHENEVER SQLERROR SQLPRINT;

EXEC SQL CONNECT TO "unix:postgresql://localhost:1237/test" AS :_thisDbConn;

snprintf( stmt, 3000, "SELECT count(*) FROM %s WHERE %s", table, where );
EXEC SQL AT :_thisDbConn PREPARE cntstmt FROM :stmt;
EXEC SQL AT :_thisDbConn EXECUTE cntstmt INTO :recCount :fnull;
EXEC SQL DEALLOCATE PREPARE cntstmt;

EXEC SQL DISCONNECT :_thisDbConn;

printf("Ergebnis: %d\n", recCount);

return 0;
}

I prepared and compiled it on both 8.4.0 and 8.3.5 and ran both programs
against both versions (all 4 combinations).

There were no errors or warnings, and the correct result was returned.

Yours,
Laurenz Albe