/* Print formatted output to string STR. Similar to vsprintf, but
additional length SIZE limit how much is written into STR. Returns
string length of formatted string (which may be larger than SIZE).
STR may be NULL, in which case nothing will be written. On error,
/* Print formatted output to string STR. Similar to vsprintf, but
additional length SIZE limit how much is written into STR. Returns
string length of formatted string (which may be larger than SIZE).
STR may be NULL, in which case nothing will be written. On error,