Messages in this thread | | | Date | Thu, 29 Apr 2004 23:46:41 +0200 (MEST) | From | Mikael Pettersson <> | Subject | Re: [PATCH][2.6.6-rc3] gcc-3.4.0 fixes |
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On Thu, 29 Apr 2004 11:30:25 +0200, Ihar 'Philips' Filipau wrote: >Mikael Pettersson wrote: >> This patch fixes three warnings from gcc-3.4.0 in 2.6.6-rc3: >> - drivers/char/ftape/: use of cast-as-lvalue >> if (get_unaligned((__u32*)ptr)) { >> - ++(__u32*)ptr; >> + ptr += sizeof(__u32); >> } else { > > Can anyone explain what is the problem with this? > To me it seems pretty ligitimate code - why it was outlawed in gcc 3.4? > > Previous code was agnostic to type of ptr, but you code presume ptr >being char pointer (to effectively increment by 4 bytes).
'ptr' _is_ a char pointer, and the code (visible in the part of the patch you didn't include) already performed pointer arithmetic on it relying on it being a char pointer. The old code had no sane reason at all for updating 'ptr' via a cast-as-lvalue.
cast-as-lvalue is not proper C, has dodgey semantics, and can always be replaced by proper C. - 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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