CentOS - Jun 2009 - RPM python subroutine for (epoch, version, release) comparation?

Hi, all,
?
?On Centos 5 I am programming RPM with python recently. ?When I read the online
RPM python programming guide at
http://docs.fedoraproject.org/drafts/rpm-guide-en/ch16s05.html, I got confused
at the EVR() function as the function returns the (epoch, version, release) as a
string ?%epoch-%version-%release?, and so the RPM ?comparing process is
simplified as string comparing ? which doesn?t look correct, am I wrong? See the
code from the page:
?
--------------------------------------------------------------------------------------
file_h = ts.hdrFromFdno(fd) 
file_ds = file_h.dsOfHeader() 
inst_ds = inst_h.dsOfHeader() 
if file_ds.EVR() >= inst_ds.EVR(): 
print "Package file is same or newer, OK to upgrade." 
else: 
print "Package file is older than installed version."
--------------------------------------------------------------------------------------
?
I?ve see another function in rpm object: rpm.versionCompare(h1,h2) which compare
two rpm headers, Am I supposed to use this function or the EVR as documented?
The former one is not well documented, though.
?
Thanks.
?
-- Robinson


      
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