[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 1 of 5] blktap: remove HAVE_BYTESWAP_H checking, since it's defined by qemu
2011/12/19 Ian Campbell <Ian.Campbell@xxxxxxxxxx>: > On Sun, 2011-12-18 at 12:48 +0000, Roger Pau Monne wrote: >> # HG changeset patch >> # User Roger Pau Monne <roger.pau@xxxxxxxxxxxxx> >> # Date 1324171782 -3600 >> # Node ID eed78eb655c40b0ac9af1b14c1cc03204f696b0b >> # Parent Âb783e76e63a99c9d87fca4974492f60af99a2e7a >> blktap: remove HAVE_BYTESWAP_H checking, since it's defined by qemu >> >> blktap was using defines set by qemu, even when the qemu config file >> is not included. Remove this checkings, and instead check if the file >> has been included before defining the necessary macros. >> >> The output error is: >> >> In file included from block-qcow.c:37:0: >> bswap.h:23:0: error: "bswap_16" redefined [-Werror] >> /usr/include/byteswap.h:30:0: note: this is the location of the >> previous definition >> bswap.h:31:0: error: "bswap_32" redefined [-Werror] >> /usr/include/byteswap.h:33:0: note: this is the location of the >> previous definition >> bswap.h:41:0: error: "bswap_64" redefined [-Werror] >> /usr/include/byteswap.h:37:0: note: this is the location of the >> previous definition >> cc1: all warnings being treated as errors >> >> Signed-off-by: Roger Pau Monne <roger.pau@xxxxxxxxxxxxx> >> >> diff -r b783e76e63a9 -r eed78eb655c4 tools/blktap/drivers/bswap.h >> --- a/tools/blktap/drivers/bswap.h  ÂSun Dec 18 02:29:42 2011 +0100 >> +++ b/tools/blktap/drivers/bswap.h  ÂSun Dec 18 02:29:42 2011 +0100 >> @@ -15,9 +15,7 @@ >> Â#define bswap_64(x) swap64(x) >> Â#else >> >> -#ifdef HAVE_BYTESWAP_H >> -#include <byteswap.h> >> -#else >> +#ifndef _BYTESWAP_H > > This is basically saying "if the user hasn't already include byteswap.h" > but it seems to rely on that header using the precise guard _BYTESWAP_H > which I presume can differ across platforms. I don't think this is a > viable approach. From what I saw _BYTESWAP_H is defined in uclibc and glibc (Solaris and NetBSD have their own preprocessor logic, so this doesn't apply to them). It's just a safeguard that avoids redefining the macros if someone has included byteswap.h behind our backs. > Given that we have our own definitions of these things any why not just > remove the ifdef and single the other #include of byteswap.h and always > use the ones we defined? > > The other alternative is to remove our own version and always include > byteswap.h. > > The right answer depends on how standardised byteswap.h is. It seems to > be in glibc but is it in uclibc and the BSD libcs? I can't find a > definitive reference but it seems like it is specified by POSIX? The solutions I see are: * Check if byteswap.h has been included (this patch). * undef bswap_* functions and define our own. * Include byteswap.h. _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |