TOUPPER(3)             FreeBSD Library Functions Manual             TOUPPER(3)

NAME
     toupper - lower case to upper case letter conversion

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <ctype.h>

     int
     toupper(int c);

DESCRIPTION
     The toupper() function converts a lower-case letter to the corresponding
     upper-case letter.  The argument must be representable as an unsigned
     char or the value of EOF.

RETURN VALUES
     If the argument is a lower-case letter, the toupper() function returns
     the corresponding upper-case letter if there is one; otherwise, the
     argument is returned unchanged.

COMPATIBILITY
     The 4.4BSD extension of accepting arguments outside of the range of the
     unsigned char type in locales with large character sets is considered
     obsolete and may not be supported in future releases.  The towupper()
     function should be used instead.

SEE ALSO
     ctype(3), isupper(3), towupper(3)

STANDARDS
     The toupper() function conforms to ISO/IEC 9899:1990 ("ISO C90").

FreeBSD 13.1-RELEASE-p6          July 25, 2010         FreeBSD 13.1-RELEASE-p6