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| -rw-r--r-- | include/stddef.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/include/stddef.h b/include/stddef.h index 275e53c..0e10989 100644 --- a/include/stddef.h +++ b/include/stddef.h @@ -28,6 +28,18 @@ * the same width and ISO C does not specify it this * way), use to indicate that a pointer does not point * to anything. + * + * Note on considerations of `NULL` being harmful: + * It is important to remember than `sizeof(NULL)` + * does not equal `sizeof(int)` on all machines. + * Therefore, in variadic arguments, it is important + * not to substitute `x` for `x != NULL`. This + * would cause horrible bugs. If you insist on not + * using `NULL`, correct substitutions would be + * `!!x` or `x != 0`. + * Note that `NULL` is genuinely harmful in C++, + * but excessive use of C++, and especially it + * features, is harmful too. */ #ifndef NULL # define NULL ((void*)0) |