Library: Localization
Function
Locale convenience function that determines if a character is a control character
#include <locale> namespace std { template <class charT> bool iscntrl(charT c, const locale& loc); }
The iscntrl() function returns true if the character passed as a parameter is a control character. Otherwise, the function returns false. The check is made using the ctype facet from the locale parameter.
ctype, locale, isalnum(), isalpha(), isdigit(), isgraph(), islower(), isprint(), ispunct(), isspace(), isupper(), isxdigit()
ISO/IEC 14882:1998 -- International Standard for Information Systems -- Programming Language C++, Section 22.1.3.1