Standalone Excel to csv conversion?

[sa212+lo at cyconix.com]

Thanks for the responses - if I can reply to everyone at once:

Joao - thanks, rows looks good, but I'm trying to move away from Python 
- I currently only need it for Excel handling

Kohei - yes, pretty much what I was expecting, thanks. Unfortunately, I 
do need xls, for at least another year or so. The C libs I've looked 
(briefly) at are:

xlnt (https://github.com/tfussell/xlnt) - looks good, but doesn't handle 
xls, and it's not obvious that it can yet export csv files

OpenXLSX (https://github.com/troldal/OpenXLSX) - doesn't seem as mature 
as xlnt; again, xlsx only, not obvious that it can export csv

Michael - good idea, at least in the short term. Both LibreOffice and 
ssconvert (gnumeric) can handle my test spreadsheets and generate csv 
output. I'm sticking with ssconvert at the moment, as I suspect that a 
gnumeric headless install is (much?) less resource intensive than a 
LibreOffice install and then running it headless (I need to run headless 
on a server). I've covered this on SO at 
https://serverfault.com/a/1099802/221197.

There are also other potential solutions - there are at least 3 program 
called xlsx2csv, for example. All 3 are minimally documented and 
probably don't work. I've tried the Python version, but can't persuade 
it to produce anything other than floating-point output for times.