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." 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> --- 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