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According to Eric Blake on 11/17/2009 6:12 AM:
> According to Alexander Nasonov on 11/17/2009 2:37 AM:
>> it fails here:
>
>> fflush.c(95): error: a value of type "__off_t={__int64_t={long long}}"
>> cannot be assigned to an entity of type "fpos_t"
>> fp_->_offset = pos;
>> ^
>> compilation aborted for fflush.c (code 2)
>> *** [fflush.o] Error code 2
>> 1 error
>
> Thanks for the report. This is a gnulib problem, so I'm adding that list.
> Actually, the real fix is to make gnulib realize how to properly assign to
> fpos_t, even when it is a struct. But this is something that Bruno may be
> more familiar with, since he wrote the code in this file.
>
Sorry for the delay, and thanks again for the report. I finally took time
on a NetBSD machine, and reproduced the problem by using CC='gcc -ansi'.
This patch fixed the issue for me, so I'm applying it.
- --
Don't work too hard, make some time for fun as well!
Eric Blake e...@byu.net
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>From 826b1b3ba7eb47ac22741eb32a623831b9e50b7f Mon Sep 17 00:00:00 2001
From: Eric Blake <e...@byu.net>
Date: Mon, 14 Dec 2009 15:42:13 -0700
Subject: [PATCH] fflush: avoid compilation error on NetBSD
On NetBSD, the system <stdio.h> header contains:
|#if (!defined(_ANSI_SOURCE) && !defined(__STRICT_ANSI__)) || defined(_LIBC)
|typedef __off_t fpos_t;
|#else
|typedef struct __sfpos {
| __off_t _pos;
|} fpos_t;
|#endif
Thus, based on compiler flags (such as using 'gcc -ansi' or the
Intel compiler), it is an error to directly set fpos_t=off_t.
* lib/fflush.c (update_fpos_cache): Use a union to safely convert
between off_t and fpos_t, since the latter is sometimes a struct.
* lib/fseeko.c (rpl_fseeko): Likewise.
Reported by Alexander Nasonov <al...@yandex.ru>.
Signed-off-by: Eric Blake <e...@byu.net>
---
ChangeLog | 8 ++++++++
lib/fflush.c | 11 ++++++++++-
lib/fseeko.c | 13 ++++++++++++-
3 files changed, 30 insertions(+), 2 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 13a4e60..b75ed74 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2009-12-16 Eric Blake <e...@byu.net>
+
+ fflush: avoid compilation error on NetBSD
+ * lib/fflush.c (update_fpos_cache): Use a union to safely convert
+ between off_t and fpos_t, since the latter is sometimes a struct.
+ * lib/fseeko.c (rpl_fseeko): Likewise.
+ Reported by Alexander Nasonov <al...@yandex.ru>.
+
2009-12-15 Eric Blake <e...@byu.net>
cloexec, dup3, fchdir: rely on fcntl
diff --git a/lib/fflush.c b/lib/fflush.c
index 0af1703..d823a34 100644
--- a/lib/fflush.c
+++ b/lib/fflush.c
@@ -91,7 +91,16 @@ static inline void
update_fpos_cache (FILE *fp, off_t pos)
{
#if defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD,
DragonFly, MacOS X, Cygwin */
- fp_->_offset = pos;
+ /* Use a union, since on NetBSD, the compilation flags determine
+ whether fpos_t is typedef'd to off_t or a struct containing a
+ single off_t member. */
+ union
+ {
+ fpos_t f;
+ off_t o;
+ } u;
+ u.o = pos;
+ fp_->_offset = u.f;
fp_->_flags |= __SOFF;
#endif
}
diff --git a/lib/fseeko.c b/lib/fseeko.c
index 8887f24..91b853d 100644
--- a/lib/fseeko.c
+++ b/lib/fseeko.c
@@ -110,7 +110,18 @@ rpl_fseeko (FILE *fp, off_t offset, int whence)
#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku,
Linux libc5 */
fp->_flags &= ~_IO_EOF_SEEN;
#elif defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD,
DragonFly, MacOS X, Cygwin */
- fp_->_offset = pos;
+ {
+ /* Use a union, since on NetBSD, the compilation flags
+ determine whether fpos_t is typedef'd to off_t or a struct
+ containing a single off_t member. */
+ union
+ {
+ fpos_t f;
+ off_t o;
+ } u;
+ u.o = pos;
+ fp_->_offset = u.f;
+ }
fp_->_flags |= __SOFF;
fp_->_flags &= ~__SEOF;
#elif defined __EMX__ /* emx+gcc */
--
1.6.5.rc1
