You're missing a semi-colon at unsigned char tes = (unsigned char)dataChar. After that your function compiles (with warnings). If it does not compile, post your complete sketch; please use code tags when posting code (and error messages) as described in How to get the best out of this forum.
dataChar is an array, test is a character, hence the cast warning. This will work
unsigned char *tes = (unsigned char*)dataChar;
But you can't print tes that way; use a for-loop to print all elements.