(PHP 4 >= 4.3.3, PHP 5, PHP 7, PHP 8)
snmp_set_valueretrieval — Specify the method how the SNMP values will be returned
method
     | SNMP_VALUE_LIBRARY | The return values will be as returned by the Net-SNMP library. | 
| SNMP_VALUE_PLAIN | The return values will be the plain value without the SNMP type information. | 
| SNMP_VALUE_OBJECT | 
           The return values will be objects with the properties value and type, where the latter
           is one of the SNMP_OCTET_STR, SNMP_COUNTER etc. constants. The
           way value is returned is based on which one of constants
           SNMP_VALUE_LIBRARY, SNMP_VALUE_PLAIN is set.
           | 
         
   总是返回 true。
  
示例 #1 Using snmp_set_valueretrieval()
<?php
 snmp_set_valueretrieval(SNMP_VALUE_LIBRARY);
 $ret = snmpget('localhost', 'public', 'IF-MIB::ifName.1');
 // $ret = "STRING: lo"
 snmp_set_valueretrieval(SNMP_VALUE_PLAIN);
 $ret = snmpget('localhost', 'public', 'IF-MIB::ifName.1');
 // $ret = "lo";
 snmp_set_valueretrieval(SNMP_VALUE_OBJECT);
 $ret = snmpget('localhost', 'public', 'IF-MIB::ifName.1');
 // stdClass Object
 // (
 //   [type] => 4        <-- SNMP_OCTET_STR, see constants
 //   [value] => lo
 // )
 snmp_set_valueretrieval(SNMP_VALUE_OBJECT | SNMP_VALUE_PLAIN);
 $ret = snmpget('localhost', 'public', 'IF-MIB::ifName.1');
 // stdClass Object
 // (
 //   [type] => 4        <-- SNMP_OCTET_STR, see constants
 //   [value] => lo
 // )
 snmp_set_valueretrieval(SNMP_VALUE_OBJECT | SNMP_VALUE_LIBRARY);
 $ret = snmpget('localhost', 'public', 'IF-MIB::ifName.1');
 // stdClass Object
 // (
 //   [type] => 4        <-- SNMP_OCTET_STR, see constants
 //   [value] => STRING: lo
 // )
?>