Re: [PATCH v1] Remove 'restrict' from 'nptr' in strtol(3)-like functions

[LIU Hao via Gcc]

在 2024-07-05 23:23, Alejandro Colomar via Gcc 写道:

Hi Martin,

On Fri, Jul 05, 2024 at 05:02:15PM GMT, Martin Uecker wrote:

But when the thing gets non-trivial, as in strtol(3), GCC misses the
-Wrestrict diagnostic, as reported in

   char*
   dumb(char* p)
     {
       strtol((const char*) &p, &p, 0);
       return p;
     }

   // warning: passing argument 2 to 'restrict'-qualified parameter
   // aliases with argument 1






--
Best regards,
LIU Hao

A pointer to `char` can alias any object, so in theory one could write code that looks like below. This piece of code is probably nonsense, but it illustrates the exact necessity of the `restrict` qualifiers:

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