ctype(3C)																 ctype(3C)

NAME

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

SYNOPSIS

       #include <ctype.h>

       int isalpha(int c);

       int isalnum(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 macros classify character-coded integer values. Each is a predicate returning non-zero for true, 0 for false. The behavior  of  these
       macros,	except	isascii(),  is	affected by the current locale (see setlocale(3C)). To modify the behavior, change the LC_TYPE category in
       setlocale(), that is, setlocale(LC_CTYPE, newlocale).  In the "C" locale, or in a locale where character type information is  not  defined,
       characters are classified according to the rules of the US-ASCII 7-bit coded character set.

       The  isascii() macro is defined on all integer values. The rest are defined only where the argument is an int, the value of which is repre-
       sentable as an unsigned char, or EOF, which is defined by the <stdio.h> header and represents end-of-file.

       Functions exist for all the macros defined below. To get the function form, the macro name must be undefined (for example, #undef isdigit).

       For macros described with Default and Standard conforming versions, standard-conforming behavior is provided for standard-conforming appli-
       cations (see standards(5)) and for applications that define __XPG4_CHAR_CLASS__ before including <ctype.h>.

   Default
       isalpha()       Tests for any character for which isupper() or islower() is true.

   Standard conforming
       isalpha()       Tests  for  any	character  for	which  isupper() or islower() is true, or any character that is one of the current locale-
		       defined set of characters for which none of iscntrl(), isdigit(), ispunct(), or isspace() is true. In "C" locale, isalpha()
		       returns true only for the characters for which isupper() or islower() is true.

       isalnum()       Tests for any character for which isalpha() or isdigit() is true (letter or digit).

       isascii()       Tests for any ASCII character, code between 0 and 0177 inclusive.

       isblank()       Tests  whether  c is a character of class blank in the current locale. This macro/function is not available to applications
		       conforming to standards prior to SUSv3. See standards(5)

       iscntrl()       Tests for any ``control character'' as defined by the character set.

       isdigit()       Tests for any decimal-digit character.

   Default
       isgraph()       Tests for any character for which ispunct(), isupper(), islower(), and isdigit() is true.

   Standard conforming
       isgraph()       Tests for any character for which isalnum() and ispunct() are true, or any character in the current locale-defined  "graph"
		       class which is neither a space ("") nor a character for which iscntrl() is true.

       islower()       Tests  for  any	character  that is a lower-case letter or is one of the current locale-defined set of characters for which
		       none of iscntrl(), isdigit(), ispunct(), isspace(), or isupper() is true. In the "C" locale, islower()  returns	true  only
		       for the characters defined as lower-case ASCII characters.

   Default
       isprint()       Tests for any character for which ispunct(), isupper(), islower(), isdigit(), and the space character ("") is true.

   Standard conforming
       isprint()       Tests  for  any	character for which iscntrl() is false, and isalnum(), isgraph(), ispunct(), the space character (""), and
		       the characters in the current locale-defined "print" class are true.

       ispunct()       Tests for any printing character which is neither a space ("") nor a character for which isalnum() or iscntrl() is true.

       isspace()       Tests for any space, tab, carriage-return, newline, vertical-tab or form-feed (standard white-space characters) or for  one
		       of  the	current  locale-defined set of characters for which isalnum() is false.  In the "C" locale, isspace() returns true
		       only for the standard white-space characters.

       isupper()       Tests for any character that is an upper-case letter or is one of the current locale-defined set of  characters	for  which
		       none  of  iscntrl(),  isdigit(), ispunct(), isspace(), or islower() is true. In the "C" locale, isupper() returns true only
		       for the characters defined as upper-case ASCII characters.

   Default
       isxdigit()      Tests for any hexadecimal-digit character ([0-9], [A-F], or [a-f]).

   Standard conforming
       isxdigit()      Tests for any hexadecimal-digit character ([0-9], [A-F], or [a-f] or the current locale-defined sets of	characters  repre-
		       senting the hexadecimal digits 10 to 15 inclusive). In the "C" locale, only

		       0 1 2 3 4 5 6 7 8 9 A B C D E F a b c d e f

		       are included.

       If the argument to any of the character handling macros is not in the domain of the function, the result is undefined. Otherwise, the macro
       or function returns non-zero if the classification is TRUE and 0 if the classification is FALSE.

USAGE

       These macros or functions can be used safely in multithreaded applications, as long as setlocale(3C) is not  being  called  to  change  the
       locale.

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       |CSI			     |Enabled			   |
       |Interface Stability	     |Standard			   |
       |MT-Level		     |MT-Safe with exceptions	   |
       +-----------------------------+-----------------------------+

       setlocale(3C), stdio(3C), ascii(5), environ(5), standards(5)

								    28 Jan 2005 							 ctype(3C)