On 08/11/2016 09:12 AM, Yuriy Kolerov wrote: > >>> Moreover the whole uClibc and every application must be compiled with >> those macros. Here is my question. Is it acceptable just to compile toolchain >> itself using CFLAGS_FOR_TARGET with those macros and don’t define them >> manually in each application? >> >> If you enable LFS support in build system (uClibc or buildroot) these macros >> will be automatically defined - no point or need to pass them as CFLAGS etc - >> infact that would be wrong IMO. > If you enable __UCLIBC_HAS_LFS__ while configuring uClibc then > _LARGEFILE64_SOURCE and _FILE_OFFSET_BITS=64 will not be defined > automatically.
What was I smoking when replying ? You are correct - these macros have to be added to each application's makefile or at top level as target C flags. > E.g. Buildroot has this generic line in Makefile for packages: > > TARGET_CPPFLAGS += -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE > -D_FILE_OFFSET_BITS=64 Actually BR dropped support for disabling LFS in 2015 - before that the line above used to be guarded by BR2_LARGEFILE. > These defines are not placed to config.h or somewhere else. They must be > defined each time you compile anything. uClibc may be built by Buildroot with > these flags by default (actually it is not true at least for ARC - Buildroot > must be fixed but it is not a subject of this discussion). However you must > define these macros manually when building every application later. Right, I stand corrected. > I don’t understand this thing - is it possible to compile uClibc with full > support of LFS (see macros above) and don’t use this feature in applications > and everything will be ok? Indeed this is the case - if you don't build with LFS, xxx64 won't even be available to begin with. > And is it possible to compile uClibc without _LARGEFILE64_SOURCE and > _FILE_OFFSET_BITS=64 and compile applications with them and everything will > be ok? This mostly likely won't work as those defines will not be present in headers to use in application. > Right now when we build toolchain for ARC using Buildroot uClibc is compiled > without them and e.g. BusyBox is compiled with -D_LARGEFILE_SOURCE > -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 ... Buildroot now assumes LFS to be default (and you can't switch it off) so everything including uClibc / Busybox has LFS enabled already. > >> So you really don't need LFS to be able to use locks - but need to make sure >> that for common generic ABI - user struct flock pairs correctly with kernel >> struct >> flock64 with or w/o LFS. But this point remains valid - for our ABI - kernel uses struct flock64 and this needs to be binary compatible with uClibc struct flock and struct flock64 (LFS only) Read the comment in libc/sysdeps/linux/common-generic/bits/stat.h -Vineet _______________________________________________ linux-snps-arc mailing list linux-snps-arc@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-snps-arc
