On Sun, 11 Jan 2026 10:00:32 -0500 [email protected] wrote: > +#define RTE_PTR_ADD(ptr, x) \ > + (__extension__ ({ \ > + /* Diagnostics suppressed for internal macro operations only. \ > + * Compiler type-checks all _Generic branches even when > unselected, \ > + * triggering warnings with no external impact. */ \ > + __rte_diagnostic_push \ > + __rte_diagnostic_ignored_wcast_qual \ > + _Pragma("GCC diagnostic ignored > \"-Wconditional-type-mismatch\"") \ > + /* Uses uintptr_t arithmetic for integer types (API > compatibility), \ > + * and char* arithmetic for pointer types (enables > optimization). */ \ > + __auto_type _ptr_result = _Generic((ptr), \ > + unsigned long long: ((void *)((uintptr_t)(ptr) + (x))), > \ > + long long: ((void *)((uintptr_t)(ptr) + (x))), > \ > + unsigned long: ((void *)((uintptr_t)(ptr) + (x))), > \ > + long: ((void *)((uintptr_t)(ptr) + (x))), > \ > + unsigned int: ((void *)((uintptr_t)(ptr) + (x))), > \ > + int: ((void *)((uintptr_t)(ptr) + (x))), > \ > + unsigned short: ((void *)((uintptr_t)(ptr) + (x))), > \ > + short: ((void *)((uintptr_t)(ptr) + (x))), > \ > + unsigned char: ((void *)((uintptr_t)(ptr) + (x))), > \ > + signed char: ((void *)((uintptr_t)(ptr) + (x))), > \ > + char: ((void *)((uintptr_t)(ptr) + (x))), > \ > + _Bool: ((void *)((uintptr_t)(ptr) + (x))), > \ > + /* Ternary with null pointer constant: per C11, if one > operand \ > + * is a null pointer constant and the other is a > pointer, the \ > + * result type is qualified per the pointer operand, > normalizing \ > + * const T* to const void* and T* to void*. */ \ > + default: _Generic((1 ? (ptr) : (void *)0), \ > + const void *: ((void *)((const char *)(ptr) + > (x))), \ > + default: ((void *)((char *)(ptr) + (x))) \ > + ) \ > + ); \ > + __rte_diagnostic_pop \ > + _ptr_result; \ > + }))
Good idea in general but the macro is way to big and therefore hard to read. The comments could be outside the macro. Any code that adds dependency on a pragma to work is brittle and likely to allow bugs through. Please figure out how to do it without.
