Author: Heejin Ahn Date: 2023-08-31T17:22:44-07:00 New Revision: ef8121b109ef0be9fe94289acbfb9736d66cff15
URL: https://github.com/llvm/llvm-project/commit/ef8121b109ef0be9fe94289acbfb9736d66cff15 DIFF: https://github.com/llvm/llvm-project/commit/ef8121b109ef0be9fe94289acbfb9736d66cff15.diff LOG: [Headers] Remove a space in NULL define There was no space in `((void *)0)` before D158709. This can cause downstream warnings in case other libraries define `NULL` as `((void*)0)`, which is the case for [[ https://www.musl-libc.org/ | musl ]]. (see `NULL` definition in https://git.musl-libc.org/cgit/musl/tree/include/stdio.h) When a macro is redefined, if the content is the same it is fine, but if it is different even in terms of a single space, clang warns: ``` ../musl/include/stdio.h:37:9: error: 'NULL' macro redefined [-Werror,-Wmacro-redefined] 37 | #define NULL ((void*)0) | ^ ``` The old code didn't have the space and it had been fine for many years, so I think there's no risk in removing it. The linter seems to prefer the space in there, but I think it has a risk of causing warnings or even errors for downstream users. Reviewed By: iana Differential Revision: https://reviews.llvm.org/D159312 Added: Modified: clang/lib/Headers/__stddef_null.h Removed: ################################################################################ diff --git a/clang/lib/Headers/__stddef_null.h b/clang/lib/Headers/__stddef_null.h index 33d0ec62fd905da..6244964ac871fea 100644 --- a/clang/lib/Headers/__stddef_null.h +++ b/clang/lib/Headers/__stddef_null.h @@ -15,5 +15,9 @@ #define NULL 0 #endif #else -#define NULL ((void *)0) +// Don't add any whitespaces in ((void*)0) below! +// musl (https://www.musl-libc.org/) redefines `NULL` as such and redefinition +// with a diff erent expression, even in terms of a single whitespace, causes a +// warning. +#define NULL ((void*)0) #endif _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
