the problem when process exit

[GoogleCodeExporter]

What steps will reproduce the problem?
1. general code:
import log "code.google.com/p/log4go"
log.Error(err)
os.Exit(-1)

2.
3.

What is the expected output? What do you see instead?
os.Exit(-1) make the process exit, but the 'err' don't be writed into log file. 
the 'err' may be buffered by the chan of 'log4go', os.Exit make the log4go 
writer(goroutine) exit too.  

What version of the product are you using? On what operating system?
lastest, Linux amd64

Please provide any additional information below.

Original issue reported on code.google.com by Marck...@gmail.com on 10 Oct 2012 at 3:17