*nix Documentation Project
·  Home
 +   man pages
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

  man pages->Linux man pages -> isalpha (3)              



NAME    [Toc]    [Back]

       isalnum, isalpha, isascii, isblank, iscntrl, isdigit, isgraph, islower,
       isprint, ispunct, isspace, isupper, isxdigit - character classification

SYNOPSIS    [Toc]    [Back]

       #include <ctype.h>

       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);

DESCRIPTION    [Toc]    [Back]

       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 (isal-
	      pha(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

	      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.

RETURN VALUE    [Toc]    [Back]

       The  values  returned  are  nonzero  if	the character c falls into the
       tested class, and a zero value if not.

CONFORMING TO    [Toc]    [Back]

       ANSI - C, BSD 4.3.  isascii() is a BSD extension and is	also  an  SVID
       extension.  isblank() is a GNU extension.

NOTE    [Toc]    [Back]

       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.

SEE ALSO    [Toc]    [Back]

       tolower(3), toupper(3), setlocale(3), ascii(7), locale(7)

GNU				  1995-09-02			    ISALPHA(3)
[ Back ]
 Similar pages
Name OS Title
ctype NetBSD character classification macros
ctype OpenBSD character classification macros
iswctype Linux wide character classification
wctype Linux wide character classification
ctype FreeBSD character classification macros
iswspace NetBSD wide character classification utilities
iswspace FreeBSD wide character classification utilities
iswspecial FreeBSD wide character classification utilities
iswxdigit NetBSD wide character classification utilities
iswupper FreeBSD wide character classification utilities
Copyright © 2004-2005 DeniX Solutions SRL
newsletter delivery service