Retrieves utf-32 string from user memory with alternative error string
user_string2_utf32:string(addr:long,err_msg:string)
addr
The user address to retrieve the string from
err_msg
The error message to return when data isn't available
This function returns a null terminated UTF-8 string converted from the UTF-32 string at a given user memory address. Reports the given error message on string copy fault or conversion error.