Question: I am wondering if Fastcgi supports unicode functions like wprintf. I receive a buffer via fread and get char\* that has unicode characters in it. I mean bytes with value above 128 . How do I process them inside fastcgi main function. A call to mbstowcs fails. 

I meant that I was using the FastCGI Developers Kit library. A java client is sending data encoded with UTF-8 , I decoded it server side using mbstring functions in php , but what is the equivalent of that gcc . What ever it is does not seem to work inside the FastCGI amin function. I looked at Fascgipp but I dont know how much it is used and how stable it is . Further I dont find lugging a huge library like boost justified for a small utility.

Answer: 
Fastcgi is protocol not an API. 
So it depend on the library you are choosing. 
Yes see library 
<http://www.nongnu.org/fastcgipp/>
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> I receive a buffer via fread and get char\* that has unicode characters in it. I mean bytes with value above 128 .
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Unicode is not the only encoding that has bytes above 128 in it. In fact, most other encodings do. You need to find out which encoding is exactly used in your web application. In any case, I don't think wprintf is going to be useful to you in any way.