ipsec編譯錯誤

ipsec-tools-0.8.0 + centOS

今天編譯出現了幾處錯誤

grabmyaddr.c:424: error: dereferencing pointer ‘sin6’ does break strict-aliasing rules
grabmyaddr.c:426: error: dereferencing pointer ‘sin6’ does break strict-aliasing rules

參考了：http://plaza.rakuten.co.jp/foreverboy/，小日本的文章

CFLAGS = -g -O2  -Wall -Werror -Wno-unused "-fno-strict-aliasing"
加上紅色的部分，第一次我看網上有這個說法還不信，後面才知道，必須在那個目錄

 

還有一處錯誤很簡單，就是指定核心標頭檔，細節忘了 。

 

"-fno-strict-aliasing" 編譯選項
有強制類型轉化，是出現問題的原因。具體應該是防止最佳化，是英文的：

     If optimization level is >= 2 in gcc-4.1, strict-aliasing is used, and this could cause probelms when a pointer is referencing to a different type of object and the object is refered thereafter by using this pointer. That is the case
in this example. So you should force the compiler to not use strict-aliasing by a argument "-fno-strict-aliasing" if you want to use "-O2" or "-O3".