Programming in a multithreaded environment requires reentrant subroutines to ensure data integrity. Use the following subroutines rather than the nonreentrant version:
| asctime_r | Converts a time value into a character array |
| getgrnam_r | Returns the next group entry in the user database that matches a specific name |
| getpwuid_r | Returns the next entry that matches a specific user ID in the use database |