[Eclipse] Error code

could not find symbol 'XXX' in index

project右鍵 → view → Rebuild

[C] 關鍵字Key word

__attribute__((unused))

消除編譯器對未使用變數的告警

eq.  char test __attribute__((unused));

----

printf("%d %s\n", __LINE__, __func__);

印出當前行號及函式名稱