Defined in header <stdio.h>

Usage declaration of a union

Defined in header <wctype.h>

Defined in header <wctype.h>

This is a reference of the core C language constructs.

Defined in header <stdlib.h>

Defined in header <wchar.h>

Specify storage duration and linkage of objects and functions: auto - automatic duration and no linkage

Defined in header <math.h>

Defined in header <ctype.h>