Is it just me or is the code above misleading? It makes it look like odbc_execute() returns a resource suitable, say, for passing to one of the odbc_fetch_* functions.

In fact, odbc_execute() returns a boolean, which simply indicates success (TRUE) or failure (FALSE). The variable to pass to odbc_fetch_* is the same one that you pass to odbc_execute():

<?php
$res = odbc_prepare($db_conn, $query_string);
if(!$res) die("could not prepare statement ".$query_string);

if(odbc_execute($res, $parameters)) {
    $row = odbc_fetch_array($res);
} else {
    // handle error
}
?>

The resource returned by odbc_prepare can be freed with odbc_free_result.

after 2 days finaly got a working code
(SQL SERVER stored procedure with parameters through ODBC)

STORED PROCEDURE

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

ALTER PROCEDURE [dbo].[sp_prev_frm_prev2]
    @id int, 
    @cli nchar(20)
AS
BEGIN
    SET NOCOUNT ON;
    --SELECT 1
END

PHP

$stmt=odbc_prepare($conn,'{call db.dbo.sp_prev_frm_prev2(?,?)}');

$params=array(1,"clie");

$result = odbc_execute($stmt, $params);

Use this example for IBM DB/2:

$q = "update TABLE set PASS=? where NAME=?";
$res = odbc_prepare ($con, $q);

$a = "secret"; $b="user";
$exc = odbc_execute($res, array($a, $b));