isalnum, isalpha, isascii, isblank, iscntrl, isdigit,
isgraph, islower, isprint, ispunct, isspace, isupper, isxdi-
git - character classification routines
int isalnum (int c);
int isalpha (int c);
int isascii (int c);
int isblank (int c);
int iscntrl (int c);
int isdigit (int c);
int isgraph (int c);
int islower (int c);
int isprint (int c);
int ispunct (int c);
int isspace (int c);
int isupper (int c);
int isxdigit (int c);
These functions check whether c, which must have the value
of an unsigned char or EOF, falls into a certain character
class according to the current locale.
checks for an alphanumeric character; it is equivalent
to (isalpha(c) || isdigit(c)).
checks for an alphabetic character; in the standard "C"
locale, it is equivalent to (isupper(c) || islower(c)).
In some locales, there may be additional characters for
which isalpha() is true--letters which are neither
upper case nor lower case.
checks whether c is a 7-bit unsigned char value that
fits into the ASCII character set. This function is a
BSD extension and is also an SVID extension.
checks for a blank character; that is, a space or a
tab. This function is a GNU extension.
checks for a control character.
checks for a digit (0 through 9).
checks for any printable character except space.
checks for a lower - case character.
checks for any printable character including space.
checks for any printable character which is not a space
or an alphanumeric character.
checks for white - space characters. In the "" "C" and
"" "POSIX" locales, these are: space, form-feed ('\f'),
newline ('\n'), carriage return ('\r'), horizontal tab
('\t'), and vertical tab ('\v').
checks for an uppercase letter.
checks for a hexadecimal digits, i.e. one of 0 1 2 3 4
5 6 7 8 9 a b c d e f A B C D E F.
The values returned are nonzero if the character c falls
into the tested class, and a zero value if not.
ANSI - C, BSD 4.3. isascii() is a BSD extension and is also
an SVID extension. isblank() is a GNU extension.
The details of what characters belong into which class
depend on the current locale. For example, isupper() will
not recognize an A - umlaut as an uppercase letter in the
default C locale.
tolower(3), toupper(3), setlocale(3),