================ @@ -0,0 +1,147 @@ +.. title:: clang-tidy - portability-avoid-platform-specific-fundamental-types + +portability-avoid-platform-specific-fundamental-types +===================================================== + +Detects fundamental types (``int``, ``short``, ``long``, ``long long``, ``char`` +, ``float``, etc) and warns against their use due to platform-dependent +behavior. + +This check detects fundamental types (``int``, ``short``, ``long``, ``float``, +``char`` and their ``unsigned`` or ``signed`` variants) and warns against their +use due to non-standard platform-dependent behavior. For example, ``long`` is +64 bits on Linux but 32 bits on Windows. There is no standard rationale or +intent for the sizes of these types. + +Instead of fundamental types, use fixed-width types such as ``int32_t`` or +implementation-defined types with standard semantics, e.g. ``int_fast32_t`` for +the fastest integer type greater than or equal to 32 bits. + +Examples +-------- + +.. code-block:: c++ + + // Bad: platform-dependent fundamental types + int global_int = 42; + short global_short = 10; + // unsigned long is 32 bits on Windows and 64 bits on Mac/Linux, so this will + // overflow depending on platform. + unsigned long global_unsigned_long = 1 << 36; + // On many systems, loading into a register must be done at the processor's + // word size. On a 64-bit system with 32-bit integers, loading an element from + // slowVec could take multiple instructions. The first will load two elements, + // and additional instructions will delete the unneeded element. ---------------- jj-marr wrote:
not sure if true on x86_64, but on embedded systems this can cause problems. https://github.com/llvm/llvm-project/pull/146970 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
