Messages in this thread | | | From | Kalle Valo <> | Subject | Re: [PATCH RFC v2] mac80211: debugfs option to force TX status frames | Date | Mon, 11 Mar 2019 16:03:38 +0200 |
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ga58taw@mytum.de writes:
> On Thu, Mar 07, 2019 at 05:42:04PM +0200, Kalle Valo wrote: >> > + len = scnprintf(buf, sizeof(buf), "%d\n", (int)local->force_tx_status); >> >> I wonder about the cast, is it guaranteed that a bool is always of the >> same size as an int? > > Why is this a problem? If a bool is smaller than an int, the compiler > emits code that will prepend the value of force_tx_status with zeros.
Let's say that a bool is a byte and int is four bytes. If you use "%d" I would guess that in that case scnprintf() writes 4 bytes, meaning that 3 bytes will be overwriting either padding or some other field in the struct.
But I'm no compiler expert so I'm not going to argue about this anymore. I just wanted to point out that that the cast looks dangerous and I would not do it.
-- Kalle Valo
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