与崩溃*为（int *）NULL = 1线程;有问题？ [英] Crashing threads with *(int*)NULL = 1; problematic?

问题描述

我在一个多线程的C应用程序中发现这一点。作者评论说，它是用来使一个自定义的断言功能的线程崩溃。 GCC是与它的罚款，但铛发出如下警告：

I found this in a multi-threaded c application. The authors commented that it's used to make a thread crash in a custom assert function. GCC is fine with it, but clang issues the following warning:

note: consider using __builtin_trap() or qualifying pointer with 'volatile'

和问题也是其中之一，对于断言函数的每个用法：

and also issues one of those, for each usage of the assert function:

warning: indirection of non-volatile null pointer will be deleted, not trap

这是怎么回事？是__builtin_trap具体到铛？我应该使用它吗？

What is going on here? Is __builtin_trap specific to clang? Should I use it?

推荐答案

写 NULL 地址是不能保证可靠的程序崩溃，这样的 GCC出台 __ builtin_trap 为

Writing to NULL address is not guaranteed to crash your program reliably, so GCC introduced __builtin_trap for that.

它看起来像铛决定走得更远，干脆和消除这种写入，几乎迫使你进入使用 __ builtin_trap 。铸造 NULL 到挥发性指针相比 __ builtin_trap ，因为它仅仅是不确定的行为。

It looks like clang decided to go further, and eliminate such writes altogether, almost forcing you into using __builtin_trap. Their other option of casting NULL to volatile pointer does not look attractive compared to __builtin_trap, because it's "merely" an undefined behavior.

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