Signed-off-by: Eric Blake <eblake@xxxxxxxxxx> --- For more on the portability pitfall, and on the fact that glibc intentionally does not comply with C99 realloc: http://austingroupbugs.net/view.php?id=400 http://sourceware.org/bugzilla/show_bug.cgi?id=12547 http://lists.gnu.org/archive/html/bug-gnulib/2011-03/msg00247.html man3/malloc.3 | 22 ++++++++++++++++++---- 1 files changed, 18 insertions(+), 4 deletions(-) diff --git a/man3/malloc.3 b/man3/malloc.3 index 4067aea..32815a1 100644 --- a/man3/malloc.3 +++ b/man3/malloc.3 @@ -113,8 +113,16 @@ is equal to zero, and .I ptr is not NULL, then the call is equivalent to -.IR free(ptr) . -Unless +.IR free(ptr) +with a return of NULL, which is compliant to C89 but in violation of +C99. C99 semantics result in leaking either the original +.I ptr +(if NULL is returned) or an unexpected new zero-size allocation, if +you are assuming GNU semantics; while GNU semantics result in a double +free when NULL is returned if you are expecting C99 semantics. It is +better to avoid a +.I size +of 0. Unless .I ptr is NULL, it must have been returned by an earlier call to .BR malloc (), @@ -162,9 +170,15 @@ was equal to 0, either NULL or a pointer suitable to be passed to is returned. If .BR realloc () -fails the original block is left untouched; it is not freed or moved. +fails and +.I size +was not 0, the original block is left untouched; it is not freed or +moved. .SH "CONFORMING TO" -C89, C99. +C89 (all functions), C99 (only +.BR malloc , +.BR calloc , +.BR free ). .SH NOTES By default, Linux follows an optimistic memory allocation strategy. This means that when -- 1.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
