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/*

FUNCTION

        <<tolower>>---translate characters to lower case

INDEX

        tolower

INDEX

        _tolower

ANSI_SYNOPSIS

        #include <ctype.h>

        int tolower(int <[c]>);

        int _tolower(int <[c]>);

TRAD_SYNOPSIS

        #include <ctype.h>

        int tolower(<[c]>);

        int _tolower(<[c]>);

DESCRIPTION

<<tolower>> is a macro which converts upper-case characters to lower

case, leaving all other characters unchanged.  It is only defined when

<[c]> is an integer in the range <<EOF>> to <<255>>.

You can use a compiled subroutine instead of the macro definition by

undefining this macro using `<<#undef tolower>>'.

<<_tolower>> performs the same conversion as <<tolower>>, but should

only be used when <[c]> is known to be an uppercase character (<<A>>--<<Z>>).

RETURNS

<<tolower>> returns the lower-case equivalent of <[c]> when it is a

character between <<A>> and <<Z>>, and <[c]> otherwise.

<<_tolower>> returns the lower-case equivalent of <[c]> when it is a

character between <<A>> and <<Z>>.  If <[c]> is not one of these

characters, the behaviour of <<_tolower>> is undefined.

PORTABILITY

<<tolower>> is ANSI C.  <<_tolower>> is not recommended for portable

programs.

No supporting OS subroutines are required.

*/

#include <_ansi.h>

#include <ctype.h>

#undef tolower

int

_DEFUN(tolower,(c),int c)

{

        return isupper(c) ? (c) - 'A' + 'a' : c;

}