LIB.RPGNAME.rpgle

Dcl-ds PARM1_Ds Extname('FILE') Qualified End-ds;
                                                    
 Incoming parameter definition                      
Dcl-pr Entry Extpgm('RPGNAME');                  
  PARM1   Char(%Len(PARM1_Ds.FIELDOFPARM1));               
End-pr;                                             

* Incoming parameter definition       
 Dcl-pi Entry;                        
   PARM1   Char(%Len(PARM1_Ds.PARM1));
 End-pi;   

pdorunexternalprogramming.php

<?php
$parm1 = "             ";

$dbh = new PDO('odbc:MYIBMI', 'user', 'pass');
$sth = $dbh->prepare("CALL SPROCNAME1(:PARM1INOUT)");

//must be length 9 or you get a null '0000067�' instead of  '10000067'
$sth->bindParam(":PARM1INOUT", $parm2inout, PDO::PARAM_STR|PDO::PARAM_INPUT_OUTPUT, 9);
$sth->execute();

SQLProcExtRpg.sql

CREATE OR REPLACE PROCEDURE LIB.SPROCNAME1 (
	INOUT PARM1 CHAR(8) )
	LANGUAGE RPGLE
	SPECIFIC LIB.SPROCNAME1
	NOT DETERMINISTIC
	NO SQL
	CALLED ON NULL INPUT
	EXTERNAL NAME 'LIB/RPGNAME'
	PARAMETER STYLE GENERAL ;