All the talk about macros this week inspired me to share this macro that **Lance Robinson** came across while maintaining a C-based system at his company. What I really appreciate about this code, well, aside from the fact that it's built into ctype.h and, aside from the fact that it has nests twenty-six ternary operators, is its very subtle bug ... can you spot it?

// Macro to normalize table names
// (all of them will be stored in upper case )
#define TO_UPPER( x )( \
( 'a' == ( x ) ) ? 'A' : \
( 'b' == ( x ) ) ? 'B' : \
( 'c' == ( x ) ) ? 'C' : \
( 'd' == ( x ) ) ? 'D' : \
( 'e' == ( x ) ) ? 'E' : \
( 'f' == ( x ) ) ? 'F' : \
( 'g' == ( x ) ) ? 'G' : \
( 'h' == ( x ) ) ? 'H' : \
( 'i' == ( x ) ) ? 'I' : \
( 'j' == ( x ) ) ? 'J' : \
( 'k' == ( x ) ) ? 'K' : \
( 'l' == ( x ) ) ? 'L' : \
( 'm' == ( x ) ) ? 'M' : \
( 'n' == ( x ) ) ? 'N' : \
( 'o' == ( x ) ) ? 'O' : \
( 'p' == ( x ) ) ? 'P' : \
( 'q' == ( x ) ) ? 'Q' : \
( 'r' == ( x ) ) ? 'R' : \
( 's' == ( x ) ) ? 'S' : \
( 't' == ( x ) ) ? 'T' : \
( 'u' == ( x ) ) ? 'U' : \
( 'v' == ( x ) ) ? 'V' : \
( 'w' == ( x ) ) ? 'W' : \
( 'x' == ( x ) ) ? 'X' : \
( 'y' == ( x ) ) ? 'Y' : \
( 'Z' == ( x ) ) ? 'Z' : ( x ) \
)