\initial {C} \entry {cascaded macros}{27} \entry {commands}{3} \entry {concatenation}{16} \entry {conditionals}{27} \initial {H} \entry {header file}{3} \initial {L} \entry {line control}{33} \initial {M} \entry {macro body uses macro}{27} \initial {N} \entry {null command}{34} \initial {O} \entry {options}{35} \entry {output format}{35} \initial {P} \entry {predefined macros}{11} \entry {preprocessor commands}{3} \initial {R} \entry {redefining macros}{18} \entry {repeated inclusion}{6} \initial {S} \entry {self-reference}{23} \entry {semicolons (after macro calls)}{21} \entry {side effects (in macro arguments)}{22} \entry {stringification}{15} \initial {U} \entry {undefining macros}{17} \entry {unsafe macros}{22}