Am 27.05.2011 um 19:22 schrieb Alexandre Raymond:
For some reason, darwin provides a symbol for fdatasync(), but
doesn't officially support it.
The manpage for fdatasync on Linux states the following:
"On POSIX systems on which fdatasync() is available,
_POSIX_SYNCHRONIZED_IO is defined in <unistd.h> to a value greater
than 0."
The Open Group Base Specification Issue 7 says this on fdatasync():
"The functionality shall be equivalent to fsync() with the symbol
_POSIX_SYNCHRONIZED_IO defined, with the exception that all I/O
operations shall be completed as defined for synchronized I/O data
integrity completion."
On unistd.h it goes on to say:
"_POSIX_SYNCHRONIZED_IO
[SIO]
The implementation supports the Synchronized Input and Output option.
If this symbol is defined in <unistd.h>, it shall be defined to be -1,
0, or 200809L."
The change history has nothing on that define and its value -1, so I'm
not convinced that this really is The Right Way to check.
In fact, unistd.h defines this value to "-1", at least on OSX 10.6.7.
Add this check to the configure file.
Signed-off-by: Alexandre Raymond <cerb...@gmail.com>
Andreas
---
configure | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)
diff --git a/configure b/configure
index a318d37..b21ef75 100755
--- a/configure
+++ b/configure
@@ -2477,7 +2477,13 @@ fi
fdatasync=no
cat > $TMPC << EOF
#include <unistd.h>
-int main(void) { return fdatasync(0); }
+int main(void) {
+#if defined(_POSIX_SYNCHRONIZED_IO) && _POSIX_SYNCHRONIZED_IO > 0
+return fdatasync(0);
+#else
+#abort Not supported
+#endif
+}
EOF
if compile_prog "" "" ; then
fdatasync=yes
--
1.7.5
