lo_export does not work - help

Hi,

I am using  libpq-fe.h and libpq-fs.h with a postgreSQL 6.4.2 database to
get images in and out the database. lo_import seems to work, but lo_export
does not. I adapted an example to get the following code running:

sprintf( img_name, "'trial.tif'" );
sprintf( sql_query, "SELECT lo_export( image.raster, %s ) from image WHERE
filename = 'image2'", img_name );
res = PQexec( conn, sql_query );
if( PQresultStatus( res ) != PGRES_COMMAND_OK ){sprintf( errbuf, "Query command to database '%s' failed:\n%s",
database,PQerrorMessage( conn ) );PQclear( res );exit_nicely( conn );return im_report_error( "from_to_db", IE_NOT_OK,
errbuf);
 
}

Anyone ever got "lo_export" running in a C-routine on Red hat Linux 5.2 ?

int from_to_db( IMAGE *in, char *filename, int frto )
{

#ifdef LINUXOid            lobjOid = 0;PGconn           *conn = NULL;PGresult       *res = NULL;
#endifint            status = IE_OK;char           in_filename[1024], out_filename[1024],
sql_query[1024], img_name[256];char        *pghost = NULL, *pgport = NULL, *pgoptions = NULL,
*pgtty = NULL;char           *database = NULL;char        errbuf[512];
im_begin_func( "from_to_db" );*errbuf = '\0';*in_filename = '\0';*out_filename = '\0';*sql_query = '\0';*img_name =
'\0';
#ifdef LINUXstrcpy( in_filename, filename );sprintf( out_filename, "/images/pvosta/trial.xxx" );pghost =
"blsbl1.janbe.jnj.com";   /* host name of the backend
 
server */pgport = NULL;                    /* port of the
backend server */pgoptions = NULL;                /* special options
to start up the backend server */pgtty = "/tmp/pgsqlbug.txt";    /* debug_fleging tty or file for the
backend server */database = "linkscil1";
/* Set up the connection */conn = PQsetdb( pghost, pgport, pgoptions, pgtty, database );/* conn = PQsetdb( NULL, NULL,
NULL,NULL, database ); */
 
/* check to see that the backend connection was successfully made */if( PQstatus( conn ) == CONNECTION_BAD ){
sprintf(errbuf, "Connection to database '%s' failed:\n%s",        database, PQerrorMessage( conn ) );    exit_nicely(
conn);    return im_report_error( "from_to_db", IE_NOT_OK, errbuf );}
 
switch( frto ){    case 0:        /* Start image import to BLOB */        res = PQexec( conn, "BEGIN" );
PQclear(res );        printf( "Importing image \"%s\" into database
 
'%s'\n", ImageName( in ), database );        lobjOid = import_image( conn, in );
        if( lobjOid == 0 ){            sprintf( errbuf, "lo_import to database '%s'
failed:\n%s",                database, PQerrorMessage( conn ) );            exit_nicely( conn );            return
im_report_error("from_to_db",
 
IE_NOT_OK, errbuf );        }                /* Send BLOB to database */        sprintf( sql_query, "INSERT INTO image
(filename,
 
area, raster ) VALUES ( 'image2', 100, lo_import( '%s' ) )", filename );        res = PQexec( conn, sql_query );
if(PQresultStatus(res) != PGRES_COMMAND_OK ){            sprintf( errbuf, "Query command to database
 
'%s' failed:\n%s",                database, PQerrorMessage( conn ) );            PQclear( res );
exit_nicely(conn );            return im_report_error( "from_to_db",
 
IE_NOT_OK, errbuf );        }
        printf( "\t succeeded as large object %u.\n",
lobjOid );                        break;    case 1:        /* Start file export from BLOB */        printf( "Exporting
image\"%s\" from database
 
'%s'\n", ImageName( in ), database );
        /* Retrieve BLOB from database */

        sprintf( img_name, "'trial.tif'" );        sprintf( sql_query, "SELECT lo_export( image.raster,
%s ) from image WHERE filename = 'image2'", img_name );        res = PQexec( conn, sql_query );        if(
PQresultStatus(res ) != PGRES_COMMAND_OK ){            sprintf( errbuf, "Query command to database
 
'%s' failed:\n%s",                database, PQerrorMessage( conn ) );            PQclear( res );
exit_nicely(conn );            return im_report_error( "from_to_db",
 
IE_NOT_OK, errbuf );        }

/*        if( export_image( conn, lobjOid, in ) < IE_OK ){            sprintf( errbuf, "lo_export from database
'%s' failed:\n%s",                database, PQerrorMessage( conn ) );            exit_nicely( conn );            return
im_report_error("from_to_db",
 
IE_NOT_OK, errbuf );        }

*/                    printf( "\tsucceeded\n" );
    break;    default:        sprintf( errbuf, "Illegal option for '%s' failed:",
database );        exit_nicely( conn );        return im_report_error( "from_to_db", IE_NOT_OK,
errbuf );    break;}
res = PQexec( conn, "END" );PQclear( res );PQfinish( conn );
if( ( status < IE_OK ) || ( im_get_status() < IE_OK ) )    return im_report_error( "from_to_db", IE_NOT_OK,
"from_to_db
failed" );

#endif
printf( "Finished\n" );
im_end_func( "from_to_db" );
return( IE_OK );
}


Regards,

Peter Van Osta, MD

Biological Imaging Laboratory
Life Sciences Department I - building 160 office 137
Janssen Research Foundation
Beerse, Belgium

tel. +32 (0)14 60.6065
fax.: +32 (0)14 60.5788