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authorMax Filippov <jcmvbkbc@gmail.com>2019-05-10 19:51:25 (GMT)
committerWaldemar Brodkorb <wbx@openadk.org>2019-05-13 07:11:01 (GMT)
commit30b85d43a7657eeac02462e8d84946358a5aa647 (patch)
tree801bb9bc01ac6d26bbd35e84a829ab62b9b03d25
parent89873385e4fa219d8dbdd708c9d92214916dc1e8 (diff)
docs/defines.txt: clarify LFS-related macros
Add description for _LARGEFILE_SOURCE, _LARGEFILE64_SOURCE, _FILE_OFFSET_BITS and __USE_LARGEFILE, __USE_LARGEFILE64 and __USE_FILE_OFFSET64 macros. Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
-rw-r--r--docs/defines.txt23
1 files changed, 20 insertions, 3 deletions
diff --git a/docs/defines.txt b/docs/defines.txt
index b23fac9..6af44bd 100644
--- a/docs/defines.txt
+++ b/docs/defines.txt
@@ -10,11 +10,28 @@ __USE_GNU, __USE_BSD, __USE_XOPEN[2K], __USE_SVID, __USE_POSIX...
If defined, user program which included us requests compat additions
from relevant standard or Unix flavor. See features.h for full list.
-__USE_FILE_OFFSET64
+_LARGEFILE_SOURCE
+ If defined, headers will provide functions fseeko and ftello.
+_LARGEFILE64_SOURCE
+ If defined, headers will in addition to data types, constants and
+ functions named xxx (e.g. off_t, struct stat, F_SETLK, ftruncate())
+ supply data types, constants and functions named xxx64 (e.g. off64_t,
+ struct stat64, F_SETLK64, ftruncate64()) known as an interface for
+ 64-bit file offsets.
__USE_LARGEFILE[64]
-_LARGEFILE[64]_SOURCE
+ Defined to 1 and used internally when built with _LARGEFILE[64]_SOURCE.
+ Undefined otherwise.
+
_FILE_OFFSET_BITS
- ???
+ Select default filesystem interface. When defined as 64 the data types,
+ constants and functions mentioned in _LARGEFILE64_SOURCE as xxx are
+ aliased to the corresponding xxx64 data types, constants and functions.
+ _FILE_OFFSET_BITS=64 enables both __USE_LARGEFILE and __USE_LARGEFILE64.
+ This flag does not affect the way libc itself is built, it only affects
+ what declarations are provided to library user.
+__USE_FILE_OFFSET64
+ Defined to 1 and used internally when built with _FILE_OFFSET_BITS=64.
+ Undefined otherwise.
__THROW
Function annotation "I do not throw anything".