020m_tolower.asciidoc

tolower

NAME

tolower - convert a character to its lower-case pendant.

SYNOPSIS

#include <ctype.h>

#define _tolower(c) ((c) - 'A' + 'a')

int tolower   (int c);
int tolower_l (int c, locale_t locale);

DESCRIPTION

Converts the given character to lowercase according to the character conversion rules defined by the currently installed C locale.

In the default "C" locale, the following uppercase letters ABCDEFGHIJKLMNOPQRSTUVWXYZ are replaced with respective lowercase letters abcdefghijklmnopqrstuvwxyz.

The above _tolower macro is a simpler version of tolower that can be used when c is known to be an uppercase character.

RETURN VALUE

Lowercase version of c or unmodified ch if no lowercase version is listed in the current C locale.

SEE ALSO

toupper

Note

The details of what constitutes an uppercase or lowercase letter depend on the current locale. For example, the default "C" locale does not know about "umlauts", so no conversion is done for them. In some non - English locales, there are lowercase letters with no corresponding uppercase equivalent; the German "sharp s" is one example.

EXAMPLE

link:src/tolower1.c[role=include]

OUTPUT

$ gcc -Wall tolower1.c
$ ./a.out
tolower(A) = a
tolower(B) = b
tolower(C) = c

EXAMPLE

link:src/tolower2.c[role=include]

OUTPUT

$ gcc -Wall tolower2.c
$ ./a.out
Aa

EXAMPLE

link:src/tolower2.c[role=include]

OUTPUT

$ gcc -Wall tolower2.c
$ ./a.out
Aa

EXAMPLE

link:src/tolower3.c[role=include]

OUTPUT

$ gcc -Wall tolower3.c
$ ./a.out
Aa Bb Cc Dd Ee Ff Gg Hh Ii Jj Kk Ll Mm Nn Oo Pp Qq Rr Ss Tt Uu Vv Ww Xx Yy Zz

in iso8859-1, tolower('0xb4') gives 0xb4
in iso8859-15, tolower('0xb4') gives 0xb8