Re: convert rtl::OUString to char *

[jg]

WideCharToMultiByte() indicates that you are working on Windows. At first you need to convert to 
UTF16 (from UTF8), and then from UTF16 to the desired code page.

Have a look at 
http://code.msdn.microsoft.com/C-UTF-8-Conversion-Helpers-22c0a664 .
jg