NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | BUGS | SEE ALSO | COLOPHON

TOUPPER(3)                    Linux Programmer's Manual                    TOUPPER(3)

NAME         top

       toupper, tolower - convert letter to upper or lower case

SYNOPSIS         top

       #include <ctype.h>

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

DESCRIPTION         top

       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 functions is
       undefined.

RETURN VALUE         top

       The value returned is that of the converted letter, or c if the conversion was
       not possible.

CONFORMING TO         top

       C89, C99, 4.3BSD.

BUGS         top

       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.

SEE ALSO         top

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

COLOPHON         top

       This page is part of release 3.23 of the Linux man-pages project.  A
       description of the project, and information about reporting bugs, can be found
       at http://www.kernel.org/doc/man-pages/.

GNU                                   1993-04-04                           TOUPPER(3)