how to enable xmlwriter in php

By install php-xml, you may enable it.
[root@localhost html]# yum install php-xml

check:

[root@localhost html]# php -m

[PHP Modules]

bz2

calendar

ctype

curl

date

dbase

dom

exif

ftp

gettext

gmp

hash

iconv

libxml

mime_magic

mysql

mysqli

openssl

pcntl

pcre

PDO

pdo_mysql

pdo_sqlite

posix

pspell

Reflection

session

shmop

SimpleXML

sockets

SPL

standard

sysvmsg

sysvsem

sysvshm

tokenizer

wddx

xml

xmlreader

xmlwriter

xsl

zlib