Fix pthread-win32.h and pthread-win32.c to provide a more complete
emulation of POSIX pthread mutexes: define PTHREAD_MUTEX_INITIALIZER
and make sure that pthread_mutex_lock() can operate on a mutex
object that's been initialized that way. Then we don't need the
duplicative platform-specific logic in default_threadlock() and
pgtls_init(), which we'd otherwise need yet a third copy of for
an upcoming bug fix.
Also, since default_threadlock() supposes that pthread_mutex_lock()
cannot fail, try to ensure that that's actually true, by getting
rid of the malloc call that was formerly involved in initializing
an emulated mutex. We can define an extra state for the spinlock
field instead.
Also, replace the similar code in ecpglib/misc.c with this version.
While ecpglib's version at least had a POSIX-compliant API, it
also had the potential of failing during mutex init (but here,
because of CreateMutex failure rather than malloc failure). Since
all of misc.c's callers ignore failures, it seems like a wise idea
to avoid failures here too.
A further improvement in this area could be to unify libpq's and
ecpglib's implementations into a src/port/pthread-win32.c file.
But that doesn't seem like a bug fix, so I'll desist for now.
In preparation for the aforementioned bug fix, back-patch to all
supported branches.
Discussion: https://postgr.es/m/264860.1707163416@sss.pgh.pa.us
c.h #includes a number of core libc header files, such as <stdio.h>.
There's no point in re-including these after having read postgres.h,
postgres_fe.h, or c.h; so remove code that did so.
While at it, also fix some places that were ignoring our standard pattern
of "include postgres[_fe].h, then system header files, then other Postgres
header files". While there's not any great magic in doing it that way
rather than system headers last, it's silly to have just a few files
deviating from the general pattern. (But I didn't attempt to enforce this
globally, only in files I was touching anyway.)
I'd be the first to say that this is mostly compulsive neatnik-ism,
but over time it might save enough compile cycles to be useful.
Windows, for better performance.
Per suggestion from Andrew Chernow, but not his patch since the underlying
code was changed to deal with return values.
should always succeed, but in the likely event of a failure we would
previously fall through *without locking* - the new code will exit(1).
Printing the error message on stderr will not work for all applications, but
it's better than nothing at all - and our API doesn't provide a way to return
the error to the caller.
Windows. The test itself is bypassed in configure as discussed, and
libpq has been updated appropriately to allow it to build in thread-safe
mode.
Dave Page
