| #ifdef FOO_LIBRARY | |
| # error Unexpected FOO_LIBRARY | |
| #endif | |
| #ifdef BAR_USE_BANG | |
| # ifndef BANG_LIBRARY | |
| # error Expected BANG_LIBRARY | |
| # endif | |
| # include "bang.h" | |
| #else | |
| # ifdef BANG_LIBRARY | |
| # error Unexpected BANG_LIBRARY | |
| # endif | |
| #endif | |
| #include "bar.h" | |
| int bar() | |
| { | |
| #ifdef BAR_USE_BANG | |
| return bang(); | |
| #else | |
| return 0; | |
| #endif | |
| } |