From 9f1bed18f9466ac886addb2f79d8e4c52fb65eb5 Mon Sep 17 00:00:00 2001 From: Paul Eggert Date: Mon, 12 Apr 2021 00:33:15 -0700 Subject: [PATCH] Further fixes for REALLOC_ZERO_BYTES_FREES comment * malloc/malloc.c (REALLOC_ZERO_BYTES_FREES): Improve comment further. --- malloc/malloc.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/malloc/malloc.c b/malloc/malloc.c index 0cd3ba78ca..e2d7b1b583 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -346,13 +346,14 @@ __malloc_assert (const char *assertion, const char *file, unsigned int line, #define REVEAL_PTR(ptr) PROTECT_PTR (&ptr, ptr) /* - REALLOC_ZERO_BYTES_FREES controls the behavior of realloc (p, 0) - when p is nonnull. If nonzero, realloc (p, 0) should free p and - return NULL. Otherwise, realloc (p, 0) should do the equivalent - of freeing p and returning what malloc (0) would return. + The REALLOC_ZERO_BYTES_FREES macro controls the behavior of realloc (p, 0) + when p is nonnull. If the macro is nonzero, the realloc call returns NULL; + otherwise, the call returns what malloc (0) would. In either case, + p is freed. Glibc uses a nonzero REALLOC_ZERO_BYTES_FREES, which + implements common historical practice. - ISO C17 says the behavior is implementation-defined here; glibc - follows historical practice and defines it to be nonzero. + ISO C17 says the realloc call has implementation-defined behavior, + and it might not even free p. */ #ifndef REALLOC_ZERO_BYTES_FREES