4.13  Future library directions

4.13.1  Errors <errno.h>

4.13.2  Character handling <ctype.h>

4.13.3  Localization <locale.h>

4.13.4  Mathematics <math.h>

4.13.5  Signal handling <signal.h>

4.13.6  Input/output <stdio.h>

4.13.7  General utilities <stdlib.h>

4.13.8  String handling <string.h>