Synopsis:

       lower_str=strupr(str)

Arguments:

       str - The string to convert to lower case

Description:  This function converts the specified string str to lower case characters.

For example:

       string="THE CAT SAT ON THE MAT"

       // This will return "the cat sat on the mat"

       upper_str=strlwr(string);

Returns:  Returns a string  with all upper case characters converted to lower case.