tolower


SYNOPSIS
       #include <ctype.h>

       int toupper(int c);
       int tolower(int c);

DESCRIPTION
       toupper() converts the letter c to upper case, if possible.

       tolower() converts the letter c to lower case, if possible.

       If c is not an unsigned char value, or EOF, the behavior of these func-
       tions is undefined.

RETURN VALUE
       The value returned is that of the converted letter, or c if the conver-
       sion was not possible.

CONFORMING TO
       C89, C99, 4.3BSD.

BUGS
       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 corre-
       sponding uppercase equivalent; the German sharp s is one example.

SEE ALSO
       isalpha(3), setlocale(3), towlower(3), towupper(3), locale(7)

COLOPHON
       This page is part of release 3.35 of the Linux  man-pages  project.   A
       description  of  the project, and information about reporting bugs, can
       be found at http://man7.org/linux/man-pages/.



GNU                               1993-04-04                        TOUPPER(3)
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