Ascertains whether a given character is a control character

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

The function iscntrl( ) tests whether its character argument is a control character. For the ASCII character set, these are the character codes from 0 through 31 and 127. The function may yield different results depending on the current locale setting for the localization category LC_CTYPE, which you can query or change using the setlocale( ) function.

If the argument is a control character, iscntrl( ) returns a nonzero value (that is, TRue); if not, the function returns 0 (false).

Example

See the example for isprint( ) in this chapter.

See Also

The corresponding C99 function for wide characters, iswcntrl( ); isalnum( ), isalpha( ), isblank( ), isdigit( ), isgraph( ), islower( ), isprint( ), ispunct( ), isspace( ), isupper( ), isxdigit( ), setlocale( )