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ISALPHA(3)		   Linux Programmer's Manual		    ISALPHA(3)

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

SYNOPSIS
       #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
       These  functions	 check	whether	c, which must have the value of	an un-
       signed char or EOF, falls into a	certain	character class	 according  to
       the current locale.

       isalnum()
	      checks for an alphanumeric character; it is equivalent to	(isal-
	      pha(c) ||	isdigit(c)).

       isalpha()
	      checks for an alphabetic character; in the standard "C"  locale,
	      it  is  equivalent  to  (isupper(c) || islower(c)).  In some lo-
	      cales, there may be additional characters	for which isalpha() is
	      true--letters which are neither upper case nor lower case.

       isascii()
	      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.

       isblank()
	      checks  for  a blank character; that is, a space or a tab.  This
	      function is a GNU	extension.

       iscntrl()
	      checks for a control character.

       isdigit()
	      checks for a digit (0 through 9).

       isgraph()
	      checks for any printable character except	space.

       islower()
	      checks for a lower-case character.

       isprint()
	      checks for any printable character including space.

       ispunct()
	      checks for any printable character which is not a	 space	or  an
	      alphanumeric character.

       isspace()
	      checks  for  white-space characters.  In the "C" and "POSIX" lo-
	      cales, these are:	space, form-feed ('\f'), newline ('\n'),  car-
	      riage  return  ('\r'),  horizontal  tab ('\t'), and vertical tab
	      ('\v').

       isupper()
	      checks for an uppercase letter.

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

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

NOTE
       The  details  of	 what characters belong	into which class depend	on the
       current locale.	For example, isupper() will not	recognize an A	-  um-
       laut as an uppercase letter in the default C locale.

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

GNU				  1995-09-02			    ISALPHA(3)

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | NOTE | SEE ALSO

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