-alpha transparent not works

[vuthecuong]

Hi,
Curently I’m learning –alpha section of IM at Usage/basic.
It said:
================================
Transparent
Similarly this ensures the alpha channel is 'active' but fully transparent.
convert moon.png -alpha transparent alpha_transparent.png
================================

But when I ran convert moon.png -alpha transparent alpha_transparent.png
It throw error: convert: UnrecognizedAlphaChannelType ‘transparent’ .
I’m I missed something in command of the article is wrong?
I’m in winXP, IM 16bit 6.4.0

Thanks and regards,

[anthony]

-alpha was not settled until IM 6.4.3-7 there was still quirks and bugs until then.

[vuthecuong]

Thanks. I will try it at home in freebsd box with latest IM
regards