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### 3.8 `isprint`, `isgraph`, `isprint_l`, `isgraph_l`—printable character predicates

Synopsis

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

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

Description
`isprint` is a macro which classifies singlebyte charset 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.

`isgraph` behaves identically to `isprint`, except that space characters are excluded.

`isprint_l`, `isgraph_l` are like `isprint`, `isgraph` but perform 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 either macro using ‘`#undef isprint`’ or ‘`#undef isgraph`’, or ‘`#undef isprint_l`’ or ‘`#undef isgraph_l`’.

Returns
`isprint`, `isprint_l` return non-zero if c is a printing character. `isgraph`, `isgraph_l` return non-zero if c is a printing character except spaces.

Portability
`isprint` and `isgraph` are ANSI C.

No supporting OS subroutines are required.