How to remove duplicated characters from char* with delemeter parameter

I'm trying to remove duplicated characters from char* with delemeter parameter using Cstring library in UTF-8 characters, but unfortunately, it doesn't work me. My code should be similar to this

char* RemoveDuplicateWord(char* buffer,char* del,char* word)

{

char* newBuffer=0x0;



return newBuffer;

}