B.2.148 -xtransition

针对 K&R C 与 Sun ISO C 之间的差异发出警告。

-xtransition 选项与 -Xa 和 -Xt 选项一起使用时将发出警告。通过适当编码，可以消除关于不同行为的所有警告消息。除非使用 -xtransition 选项，否则不再出现以下警告：

• \a is ISO C “alert” character

• \x is ISO C hex escape

• bad octal digit

• base type is really type tag: name

• comment is replaced by “##”

• comment does not concatenate tokens

• declaration introduces new type in ISO C: type tag

• macro replacement within a character constant

• macro replacement within a string literal

• no macro replacement within a character constant

• no macro replacement within a string literal

• operand treated as unsigned

• trigraph sequence replaced

• ISO C treats constant as unsigned: operator

• semantics of operator change in ISO C; use explicit cast