Messages in this thread | | | Date | Sun, 18 Sep 2005 10:31:36 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: p = kmalloc(sizeof(*p), ) |
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On Sun, 18 Sep 2005, Al Viro wrote: > > That's why you do > *p = (struct foo){....}; > instead of > memset(p, 0, sizeof...); > p->... =...;
Actually, some day that migth be a good idea, but at least historically, gcc has really really messed that kind of code up.
Last I looked, depending on what the initializer was, gcc would create a temporary struct on the stack first, and then do a "memcpy()" of the result. Not only does that obviously generate a lot of extra code, it also blows your kernel stack to kingdom come.
So be careful out there, and check what code it generates first. With at least a few versions of gcc.
(For _small_ structures it's wonderful. As far as I can tell, gcc does a pretty good job on structs that are just a single long-word in size).
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