7.4.1.3 The isblank function
Synopsis
#include <ctype.h>
int isblank(int c);
Description
The isblank function tests for any character that is a standard blank character or is one of a locale-specific set of characters for which isspace is true and that is used to separate words within a line of text. The standard blank characters are the following: space (’ ‘), and horizontal tab (’\t’). In the “C” locale, isblank returns true only for the standard blank characters.