3.4 isblank, isblank_l—blank character predicate

Synopsis

#include <ctype.h>
int isblank(int c);

#include <ctype.h>
int isblank_l(int c, locale_t locale);

Description
isblank is a function which classifies singlebyte charset values by table lookup. It is a predicate returning non-zero for blank characters, and 0 for other characters. It is defined only if c is representable as an unsigned char or if c is EOF.

isblank_l is like isblank but performs the check based on the locale specified by the locale object locale. If locale is LC_GLOBAL_LOCALE or not a valid locale object, the behaviour is undefined.

Returns
isblank, isblank_l return non-zero if c is a blank character.

Portability
isblank is C99. isblank_l is POSIX-1.2008.

No supporting OS subroutines are required.