htod puts the D translation inside a comment in some cases: #define FOO 42 /* hello world */ #define BAR 24 Turns into: /* Converted to D from test.h by htod */ module test; //C #define FOO 42 /* hello const FOO = 42; world */ //C #define BAR 24 const BAR = 24; Notice the D FOO is inside the hello world comment.