Create the file named in the character string specified by c-addr and u, and open it with file access method fam. The meaning of values of fam is implementation defined. If a file with the same name already exists, recreate it as an empty file.
If the file was successfully created and opened, ior is zero, fileid is its identifier, and the file has been positioned to the start of the file.
Otherwise, ior is the implementation-defined I/O result code and fileid is undefined.