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LibPqEasy, binary cursor, x86-64, fetch(int4) problem?

From: "Mariano Reingart" <mariano(at)nsis(dot)com(dot)ar>
To: <pgsql-interfaces(at)postgresql(dot)org>
Subject: LibPqEasy, binary cursor, x86-64, fetch(int4) problem?
Date: 2006-02-11 23:28:25
Message-ID: 000301c62f62$dbd72b90$0300000a@PC1 (view raw or flat)
Thread:
Lists: pgsql-interfaces
Hi, I recently moved a simple application from a 32bit Intel to a new AMD64 
server (migrated from Postgres 7.2 to 8.1.2 and LibPqEasy 3.0.4), running 
Slamd64 (Slackware port to the AMD64). Everything compiled just fine but the 
applicattion didn't work as expected.
When I look into the tables (with psql) I see strange values in int4 columns 
like ( 16777216, 402653184, 1124073472, ...) instead of normal ones (1, 24, 
67)
Looking at application logs I found that libpqeasy is returning bad values 
in fetch( &int4 ) functions.
Thinking that my code is wrong, I run pginsert example from libpgeasy and it 
didn't work either.
Using text cursors (not binary) and atoi() solved the problem.

Here is a sample code to reproduce the bug, adapted from 
/libpgeasy-3.0.4/examples/pginsert.c:

#include <stdio.h>
#include <unistd.h>
#include "libpq-fe.h"
#include "libpgeasy.h"

int main(void) {
    int aint;
    char astring[1024];

    connectdb("dbname=fichadas");
    on_error_stop();


    doquery("BEGIN WORK");
    doquery("CREATE TABLE testfetch(aint int4)");
    doquery("INSERT INTO testfetch (aint) VALUES ( 1 )");


    /* this will print a strange number like 16777216 instead of 1: */

    doquery("DECLARE c_testfetch BINARY CURSOR FOR SELECT aint FROM 
testfetch WHERE aint=1");
    doquery("FETCH ALL IN c_testfetch");

    fetch(&aint);
    printf("aint=%d\n",aint);


    /* this will print a correct value: */

    doquery("DECLARE c2_testfetch CURSOR FOR SELECT aint FROM testfetch 
WHERE aint=1");
    doquery("FETCH ALL IN c2_testfetch");

    fetch(astring);
    printf("atoi(astring)=%d\n",atoi(astring));

    return 0;
}

/* ------------------------------- */

gcc -o test1 test1.c -lpgeasy

Output:

aint=16777216
atoi(astring)=1

Hope this helps,
Regards,
Mariano Reingart 


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