qmail queue

[Eric Dahnke]

Hello list,

DESCRIPTION                                                       
       qmail-queue  reads  a  mail message from descriptor 0.  It 
       then reads envelope information  from  descriptor  1.

In reference to this, I thought descriptor 0 was STDIN and descriptor 1
was STDOUT, How can qmail-queue read envelop information from descriptor
1.

- thx eric