Returns a string for the current machine’s hostname (including its domain).
Returns an integer identifying the current process within the operating system.
Truncates or extends the given file so that it is n-bytes long. If the file does not exist, or if the process does not have sufficient privilege to truncate the file, the exn:fail exception is raised.
WARNING: under Unix, the implementation assumes that the system’s ftruncate function accepts a long long second argument.