tolower(3) [netbsd man page]

TOLOWER(3)						   BSD Library Functions Manual 						TOLOWER(3)

NAME

     tolower -- upper case to lower case letter conversion

LIBRARY

     Standard C Library (libc, -lc)

SYNOPSIS

     #include <ctype.h>

     int
     tolower(int c);

DESCRIPTION

     The tolower() function converts an upper-case letter to the corresponding lower-case letter.

RETURN VALUES

     If the argument is an upper-case letter, the tolower() function returns the corresponding lower-case letter if there is one; otherwise the
     argument is returned unchanged.

SEE ALSO

     ctype(3), isalnum(3), isalpha(3), isascii(3), iscntrl(3), isdigit(3), isgraph(3), islower(3), isprint(3), ispunct(3), isspace(3), isupper(3),
     isxdigit(3), stdio(3), toascii(3), toupper(3), ascii(7)

STANDARDS

     The tolower() function conforms to ANSI X3.159-1989 (``ANSI C89'').

CAVEATS

     The argument to tolower() must be EOF or representable as an unsigned char; otherwise, the behavior is undefined.	See the CAVEATS section of
     ctype(3) for more details.

BSD
								  April 17, 2008							       BSD

CTYPE(2)							System Calls Manual							  CTYPE(2)

NAME

       isalpha,  isupper,  islower, isdigit, isxdigit, isalnum, isspace, ispunct, isprint, isgraph, iscntrl, isascii, toascii, _toupper, _tolower,
       toupper, tolower - ASCII character classification

SYNOPSIS

       #include <u.h>
       #include <libc.h>
       #include <ctype.h>

       isalpha(c)

       isupper(c)

       islower(c)

       isdigit(c)

       isxdigit(c)

       isalnum(c)

       isspace(c)

       ispunct(c)

       isprint(c)

       isgraph(c)

       iscntrl(c)

       isascii(c)

       _toupper(c)

       _tolower(c)

       toupper(c)

       tolower(c)

       toascii(c)

DESCRIPTION

       These macros classify ASCII-coded integer values by table lookup.  Each is a predicate returning nonzero for true, zero for false.  Isascii
       is defined on all integer values; the rest are defined only where isascii is true and on the single non-ASCII value EOF; see fopen(2).

       isalpha	c is a letter, a-z or A-Z

       isupper	c is an upper case letter, A-Z

       islower	c is a lower case letter, a-z

       isdigit	c is a digit, 0-9

       isxdigit c is a hexadecimal digit, 0-9 or a-f or A-F

       isalnum	c is an alphanumeric character, a-z or A-Z or 0-9

       isspace	c is a space, horizontal tab, newline, vertical tab, formfeed, or carriage return (0x20, 0x9, 0xA, 0xB, 0xC, 0xD)

       ispunct	c is a punctuation character (one of !"#$%&'()*+,-./:;<=>?@[]^_`{|}~)

       isprint	c is a printing character, 0x20 (space) through 0x7E (tilde)

       isgraph	c is a visible printing character, 0x21 (exclamation) through 0x7E (tilde)

       iscntrl	c is a delete character, 0x7F, or ordinary control character, 0x0 through 0x1F

       isascii	c is an ASCII character, 0x0 through 0x7F

       Toascii is not a classification macro; it converts its argument to ASCII range by anding with 0x7F.

       If  c is an upper case letter, tolower returns the lower case version of the character; otherwise it returns the original character.  Toup-
       per is similar, returning the upper case version of a character or the original character.  Tolower and toupper are functions; _tolower and
       _toupper are corresponding macros which should only be used when it is known that the argument is upper case or lower case, respectively.

   Alef
       These routines are not provided in Alef.

SOURCE

       /sys/include/ctype.h
	      for the macros.

       /sys/src/libc/port/ctype.c
	      for the tables.

BUGS

       These macros are ASCII-centric.

																	  CTYPE(2)