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CTYPE(3V)							     CTYPE(3V)

NAME
       ctype,  conv,  isalpha,	isupper,  islower, isdigit, isxdigit, isalnum,
       isspace,	ispunct, isprint, iscntrl, isascii, isgraph, toupper, tolower,
       toascii - character classification and conversion macros	and functions

SYNOPSIS
       #include	<ctype.h>

       isalpha(c)

       ...

DESCRIPTION
   Character Classification Macros
       These  macros  classify character-coded integer values according	to the
       rules of	the coded character set	defined	by the character type informa-
       tion  in	 the program's locale (category	LC_CTYPE).  On program startup
       the LC_CTYPE category of	locale is equivalent to	the "C"	locale.

       In the "C" locale, or in	a locale where the character type  information
       is not defined, characters are classified according to the rules	of the
       US-ASCII	7-bit coded character set.  The	control	characters  are	 those
       below 040 (and the single byte 0177) (DEL).  See	ascii(7).

       In all cases that argument is an	int, the value of which	must be	repre-
       sentable	as an unsigned char or must equal the value of the macro  EOF.
       If the argument has any other value, the	behavior is undefined.

       Each  is	a predicate returning nonzero for true,	zero for false.	 isas-
       cii() is	defined	on all integer values.

       isalpha(c)	   c is	a letter.

       isupper(c)	   c is	an upper case letter.

       islower(c)	   c is	a lower	case letter.

       isdigit(c)	   c is	a digit	[0-9].

       isxdigit(c)	   c is	a hexadecimal digit [0-9], [A-F], or [a-f].

       isalnum(c)	   c is	an alphanumeric	character, that	 is,  c	 is  a
			   letter or a digit.

       isspace(c)	   c  is  a  SPACE, TAB, RETURN, NEWLINE, FORMFEED, or
			   vertical tab	character.

       ispunct(c)	   c is	a punctuation character	(neither  control  nor
			   alphanumeric).

       isprint(c)	   c is	a printing character.

       iscntrl(c)	   c is	a delete character or ordinary control charac-
			   ter.

       isascii(c)	   c is	an ASCII character, code less than 0200.

       isgraph(c)	   c is	a visible graphic character.

   Character Conversion	Macros
       toascii(c)
	      Masks c with the correct value so	that c is guaranteed to	be  an
	      ASCII  character	in the range 0 through 0x7f.  Will not perform
	      mapping from a non-ASCII coded character set into	ASCII.

   Character Conversion	Functions
       These functions perform simple conversions on single characters.	  They
       replace	the previous macro definitions which did not extend to support
       variant settings	of the LC_CTYPE	locale category.

       toupper(c)	   Converts c  to  its	upper-case  equivalent.	  This
			   function  works  correctly  for all coded character
			   sets	and all	characters within such	sets  selected
			   by a	valid setting of the LC_CTYPE locale category.

       tolower(c)	   Converts  c	to  its	 lower-case  equivalent.  This
			   function works correctly for	 all  coded  character
			   sets	 and  all characters within such sets selected
			   by a	valid setting of the LC_CTYPE locale category.

       If the argument to any of these macros is not  in  the  domain  of  the
       function, the result is undefined.

SYSTEM V DESCRIPTION
   Character Conversion	Macros
       The  macros  _toupper()	and  _tolower()	are faster than	the equivalent
       functions (toupper() and	tolower()) but only work  properly  on	a  re-
       stricted	 range of characters, and will not work	on a LC_CTYPE category
       other than the default "C" (ASCII).

       These macros perform simple conversions on single characters.

       _toupper(c)	   converts c to  its  upper-case  equivalent.	 Note:
			   This	only works where c is known to be a lower-case
			   character to	start with (presumably	checked	 using
			   islower()).

       _tolower(c)	   converts  c	to  its	 lower-case equivalent.	 Note:
			   This	only works where c is known to be a upper-case
			   character  to  start	with (presumably checked using
			   isupper()).

SEE ALSO
       setlocale(3V), ascii(7),	iso_8859_1(7)

				11 January 1990			     CTYPE(3V)

NAME | SYNOPSIS | DESCRIPTION | SYSTEM V DESCRIPTION | SEE ALSO

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