From d8f3ab77d99dc6603b343fdf52b64ac7fec91a21 Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" Date: Tue, 20 Mar 2012 10:51:23 +0000 Subject: [PATCH] libfuse: don't force -D_FILE_OFFSET_BITS=64 in pkgconfig file. FUSE_CFLAGS defines -D_FILE_OFFSET_BITS=64. There are three problems with this: (1) A larger program using libfuse might have modules compiled with and without FUSE_CFLAGS, which, if LFS is not enabled and the platform is 32 bit, would result in a fatal mix of 32 and 64 bit off_t. (This would, of course, be a bug, but I think there is a better way to detect this -- see below) (2) Programs may need to be adjusted to support LFS. It's the intention of the LFS standard that the _programmer_ enables LFS once the program has been checked/adjusted. (3) _FILE_OFFSET_BITS does not need to be defined at all on 64 bit Linux. 64 bit off_t is the default there. So I think it's better not to force -D_FILE_OFFSET_BITS=64, and because of (3) I also think you shouldn't test for it. However off_t must still be 64 bits, so how to enforce that? C1X will define static assertions[1], and these can be used to check the size of off_t. Not all compilers support static assertions yet, although several do. Therefore I have surrounded the static assertion with a conservative check that the compiler is GCC >= 4.6. In the long run, this test can be removed and you can just use 'static_assert'. --- ChangeLog | 3 +++ include/fuse_common.h | 19 ++++++++++++++----- 2 files changed, 17 insertions(+), 5 deletions(-) diff --git a/ChangeLog b/ChangeLog index 511c694..2021e81 100644 --- a/ChangeLog +++ b/ChangeLog @@ -6,6 +6,9 @@ * libfuse: use O_CLOEXEC flag when opening /dev/fuse device. Patch by Richard W.M. Jones + * libfuse: don't force -D_FILE_OFFSET_BITS=64 in pkgconfig file. + Patch by Richard W.M. Jones + 2013-02-19 Miklos Szeredi * fuse_daemonize(): chdir to "/" even if not running in the diff --git a/include/fuse_common.h b/include/fuse_common.h index 78d3ce4..af16203 100644 --- a/include/fuse_common.h +++ b/include/fuse_common.h @@ -27,11 +27,6 @@ #define FUSE_MAKE_VERSION(maj, min) ((maj) * 10 + (min)) #define FUSE_VERSION FUSE_MAKE_VERSION(FUSE_MAJOR_VERSION, FUSE_MINOR_VERSION) -/* This interface uses 64 bit off_t */ -#if _FILE_OFFSET_BITS != 64 -#error Please add -D_FILE_OFFSET_BITS=64 to your compile flags! -#endif - #ifdef __cplusplus extern "C" { #endif @@ -483,4 +478,18 @@ void fuse_remove_signal_handlers(struct fuse_session *se); } #endif + +/* + * This interface uses 64 bit off_t. + * + * On 32bit systems please add -D_FILE_OFFSET_BITS=64 to your compile flags! + */ + +#if defined(__GNUC__) && (__GNUC__ > 4 || __GNUC__ == 4 && __GNUC_MINOR__ >= 6) && !defined __cplusplus +_Static_assert(sizeof(off_t) == 8, "fuse: off_t must be 64bit"); +#else +struct _fuse_off_t_must_be_64bit_dummy_struct \ + { unsigned _fuse_off_t_must_be_64bit:((sizeof(off_t) == 8) ? 1 : -1); }; +#endif + #endif /* _FUSE_COMMON_H_ */ -- 2.11.4.GIT