Messages in this thread | | | Subject | Re: Invalid compilation without -fno-strict-aliasing | Date | Wed, 26 Feb 2003 17:47:48 -0300 | From | Horst von Brand <> |
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Falk Hueffner <falk.hueffner@student.uni-tuebingen.de> said: > Horst von Brand <vonbrand@inf.utfsm.cl> writes: > > Jean Tourrilhes <jt@bougret.hpl.hp.com> said: > > > if((stream + event_len) < ends) { > > > iwe->len = event_len; > > > memcpy(stream, (char *) iwe, event_len); > > > stream += event_len; > > > } > > > return stream; > > > } > > > > The compiler is free to assume char *stream and struct iw_event *iwe > > point to separate areas of memory, due to strict aliasing. > > The relevant paragraph of the C99 standard is: > > An object shall have its stored value accessed only by an lvalue > expression that has one of the following types: [...] > -- a character type.
(char *) gives you a (pointer to) a character type.
> I can't really spot any lvalue here that might violate this rule. It > would be nice if somebody could report a bug with a testcase.
stream and (char *) iwe -- Dr. Horst H. von Brand User #22616 counter.li.org Departamento de Informatica Fono: +56 32 654431 Universidad Tecnica Federico Santa Maria +56 32 654239 Casilla 110-V, Valparaiso, Chile Fax: +56 32 797513 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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