4 ms·

I don't think pointer tagging (in and of itself, when implemented correctly for a particular platform) is ever undefined behavior. Rather, it is implementation-

I don't think pointer tagging (in and of itself, when implemented correctly for a particular platform) is ever undefined behavior. Rather, it is implementation-defined behavior - the result of converting a pointer to an integer is not specified, and could in theory be anything, so you have to know how your compiler and platform behave.

RossBencina 1y ago
We pray that it is implementation defined. According to some [1] even arithmetic on intptr_t is UB, let alone bit operations. [1] https://stackoverflow.com/a/64863331/2013747 https://stackoverflow.com/a/64863331/2013747
- deleted 1y ago
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- gpderetta 1y ago
  Eh, that's about strictly conforming programs. In practice the vast majority of programs are going to use platform facilities and extensions (POSIX for example) while still being conforming.