3.10 isspace, isspace_l—whitespace character predicate

Synopsis

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

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

Description
isspace is a macro which classifies singlebyte charset values by table lookup. It is a predicate returning non-zero for whitespace characters, and 0 for other characters. It is defined only when isascii(c) is true or c is EOF.

isspace_l is like isspace 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.

You can use a compiled subroutine instead of the macro definition by undefining the macro using ‘#undef isspace’ or ‘#undef isspace_l’.

Returns
isspace, isspace_l return non-zero if c is a space, tab, carriage return, new line, vertical tab, or formfeed (0x09–0x0D, 0x20), or one of the other space characters in non-ASCII charsets.

Portability
isspace is ANSI C. isspace_l is POSIX-1.2008.

No supporting OS subroutines are required.