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mirror of https://github.com/postgres/postgres.git synced 2025-07-27 12:41:57 +03:00

Probe for preadv/pwritev in a more macOS-friendly way.

Apple's mechanism for dealing with functions that are available
in only some OS versions confuses AC_CHECK_FUNCS, and therefore
AC_REPLACE_FUNCS.  We can use AC_CHECK_DECLS instead, so long as
we enable -Werror=unguarded-availability-new.  This allows people
compiling for macOS to control whether or not preadv/pwritev are
used by setting MACOSX_DEPLOYMENT_TARGET, rather than supplying
a back-rev SDK.  (Of course, the latter still works, too.)

James Hilliard

Discussion: https://postgr.es/m/20210122193230.25295-1-james.hilliard1@gmail.com
This commit is contained in:
Tom Lane
2021-07-12 19:17:35 -04:00
parent 9b450b1f1e
commit e75da4f1b6
5 changed files with 161 additions and 38 deletions

View File

@ -142,6 +142,14 @@
don't. */
#undef HAVE_DECL_POSIX_FADVISE
/* Define to 1 if you have the declaration of `preadv', and to 0 if you don't.
*/
#undef HAVE_DECL_PREADV
/* Define to 1 if you have the declaration of `pwritev', and to 0 if you
don't. */
#undef HAVE_DECL_PWRITEV
/* Define to 1 if you have the declaration of `RTLD_GLOBAL', and to 0 if you
don't. */
#undef HAVE_DECL_RTLD_GLOBAL
@ -421,9 +429,6 @@
/* Define to 1 if you have the `pread' function. */
#undef HAVE_PREAD
/* Define to 1 if you have the `preadv' function. */
#undef HAVE_PREADV
/* Define to 1 if you have the `pstat' function. */
#undef HAVE_PSTAT
@ -445,9 +450,6 @@
/* Define to 1 if you have the `pwrite' function. */
#undef HAVE_PWRITE
/* Define to 1 if you have the `pwritev' function. */
#undef HAVE_PWRITEV
/* Define to 1 if you have the `random' function. */
#undef HAVE_RANDOM

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@ -39,13 +39,13 @@ struct iovec
/* Define a reasonable maximum that is safe to use on the stack. */
#define PG_IOV_MAX Min(IOV_MAX, 32)
#ifdef HAVE_PREADV
#if HAVE_DECL_PREADV
#define pg_preadv preadv
#else
extern ssize_t pg_preadv(int fd, const struct iovec *iov, int iovcnt, off_t offset);
#endif
#ifdef HAVE_PWRITEV
#if HAVE_DECL_PWRITEV
#define pg_pwritev pwritev
#else
extern ssize_t pg_pwritev(int fd, const struct iovec *iov, int iovcnt, off_t offset);

View File

@ -245,6 +245,8 @@ sub GenerateFiles
HAVE_DECL_LLVMGETHOSTCPUFEATURES => 0,
HAVE_DECL_LLVMORCGETSYMBOLADDRESSIN => 0,
HAVE_DECL_POSIX_FADVISE => undef,
HAVE_DECL_PREADV => 0,
HAVE_DECL_PWRITEV => 0,
HAVE_DECL_RTLD_GLOBAL => 0,
HAVE_DECL_RTLD_NOW => 0,
HAVE_DECL_STRLCAT => undef,
@ -335,7 +337,6 @@ sub GenerateFiles
HAVE_PPC_LWARX_MUTEX_HINT => undef,
HAVE_PPOLL => undef,
HAVE_PREAD => undef,
HAVE_PREADV => undef,
HAVE_PSTAT => undef,
HAVE_PS_STRINGS => undef,
HAVE_PTHREAD => undef,
@ -343,7 +344,6 @@ sub GenerateFiles
HAVE_PTHREAD_IS_THREADED_NP => undef,
HAVE_PTHREAD_PRIO_INHERIT => undef,
HAVE_PWRITE => undef,
HAVE_PWRITEV => undef,
HAVE_RANDOM => undef,
HAVE_READLINE_H => undef,
HAVE_READLINE_HISTORY_H => undef,