3.9 isspace—whitespace character predicate

Synopsis

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

Description
isspace is a macro which classifies ASCII integer 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.

You can use a compiled subroutine instead of the macro definition by undefining the macro using `#undef isspace'.

Returns
isspace returns non-zero if c is a space, tab, carriage return, new line, vertical tab, or formfeed (0x09–0x0D, 0x20).

Portability
isspace is ANSI C.

No supporting OS subroutines are required.