Re: pg_preadv() and pg_pwritev()

On 11.01.2021 05:59, Thomas Munro wrote:
> Since only sifaka has managed to return a result so far (nice CPU), I
> had plenty of time to notice that macOS Big Sur has introduced
> preadv/pwritev. They were missing on Catalina[1].
>
> [1] https://cirrus-ci.com/task/6002157537198080

Hi, Thomas!

Indeed, pwritev is not available on macOS Catalina. So I get compiler
warnings about that:

/Users/shinderuk/src/pgwork/devel/build/../src/port/pwrite.c:117:10:
warning: 'pwritev' is only available on macOS 11.0 or newer
[-Wunguarded-availability-new]
part = pg_pwritev(fd, iov, iovcnt, offset);
^~~~~~~~~~
/Users/shinderuk/src/pgwork/devel/build/../src/include/port/pg_iovec.h:49:20:
note: expanded from macro 'pg_pwritev'
#define pg_pwritev pwritev
^~~~~~~
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX11.1.sdk/usr/include/sys/uio.h:104:9:
note: 'pwritev' has been marked as being introduced in macOS 11.0 here,
but the deployment target is macOS
10.15.0
ssize_t pwritev(int, const struct iovec *, int, off_t)
__DARWIN_NOCANCEL(pwritev) __API_AVAILABLE(macos(11.0), ios(14.0),
watchos(7.0), tvos(14.0));
^
/Users/shinderuk/src/pgwork/devel/build/../src/port/pwrite.c:117:10:
note: enclose 'pwritev' in a __builtin_available check to silence this
warning
part = pg_pwritev(fd, iov, iovcnt, offset);
^~~~~~~~~~
/Users/shinderuk/src/pgwork/devel/build/../src/include/port/pg_iovec.h:49:20:
note: expanded from macro 'pg_pwritev'
#define pg_pwritev pwritev
^~~~~~~
1 warning generated.
(... several more warnings ...)

And initdb fails:

running bootstrap script ... dyld: lazy symbol binding failed: Symbol
not found: _pwritev
Referenced from: /Users/shinderuk/src/pgwork/devel/install/bin/postgres
Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: _pwritev
Referenced from: /Users/shinderuk/src/pgwork/devel/install/bin/postgres
Expected in: /usr/lib/libSystem.B.dylib

Regards.

--
Sergey Shinderuk
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company