3.7 isprint, isgraph—printable character predicates

Synopsis

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

Description
isprint is a macro which classifies ASCII integer values by table lookup. It is a predicate returning non-zero for printable characters, and 0 for other character arguments. It is defined only if c is representable as an unsigned char or if c is EOF.

You can use a compiled subroutine instead of the macro definition by undefining either macro using `#undef isprint' or `#undef isgraph'.

Returns
isprint returns non-zero if c is a printing character, (0x20–0x7E). isgraph behaves identically to isprint, except that the space character (0x20) is excluded.

Portability
isprint and isgraph are ANSI C.

No supporting OS subroutines are required.