Horton

Re: Cleaning up historical portability baggage

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Andrew Dunstan <andrew@dunslane.net>, Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2022-07-24T00:23:06Z
Lists: pgsql-hackers 
Thomas Munro <thomas.munro@gmail.com> writes:
> Here are some more, a couple of which I posted before but I've now
> gone a bit further with them in terms of removing configure checks
> etc:

After looking through these briefly, I'm pretty concerned about
whether this won't break our Cygwin build in significant ways.
For example, lorikeet reports "HAVE_SETSID 1", a condition that
you want to replace with !WIN32.  The question here is whether
or not WIN32 is defined in a Cygwin build.  I see some places
in our code that believe it is not, but others that believe that
it is --- and the former ones are mostly like
	#if defined(__CYGWIN__) || defined(WIN32)
which means they wouldn't actually fail if they are wrong about that.

More generally, I'm not exactly convinced that changes like
this are a readability improvement:

-#ifdef HAVE_SETSID
+#ifndef WIN32

I'd rather not have the code cluttered with a sea of
indistinguishable "#ifndef WIN32" tests when some of them could be
more specific and more mnemonic.  So I think we'd be better off
leaving that as-is.  I don't mind nuking the configure-time test
and hard-wiring "#define HAVE_SETSID 1" somewhere, but changing
the code's #if tests doesn't seem to bring any advantage.

Specific to 0001, I don't especially like what you did to
src/port/dlopen.c.  The original intent (and reality until
not so long ago) was that that would be a container for
various dlopen replacements.  Well, okay, maybe there will
never be any more besides Windows, but I think then we should
either rename the file to (say) win32dlopen.c or move it to
src/backend/port/win32.  Likewise for link.c in 0007 and
pread.c et al in 0011.  (But 0010 is fine, because the
replacement code is already handled that way.)

OTOH, 0012 seems to immediately change pread.c et al back
to NOT being Windows-only, though it's hard to tell for
sure because the configure support seems all wrong.
I'm quite confused by those two patches ... are they really
correct?

			regards, tom lane

Commits

  1. Make sure IOV_MAX is defined.

  2. Doc: Abstract AF_UNIX sockets don't work on Windows.

  3. Clean up inconsistent use of fflush().

  4. Remove configure probe for sockaddr_in6 and require AF_INET6.

  5. Remove configure probes for sockaddr_storage members.

  6. Remove configure probe for netinet/tcp.h.

  7. Fix macro problem with gai_strerror on Windows.

  8. Remove configure probe for net/if.h.

  9. mstcpip.h is not missing on MinGW.

  10. Remove dead ifaddr.c fallback code.

  11. Remove configure probe for gethostbyname_r.

  12. Remove replacement code for getaddrinfo.

  13. Remove configure probe for struct sockaddr_storage.

  14. Remove HAVE_UNIX_SOCKETS.

  15. Remove configurability of PPC spinlock assembly code.

  16. Remove configure probe for shl_load library.

  17. Remove configure probe for sys/select.h.

  18. Remove configure probes for sys/un.h and struct sockaddr_un.

  19. Remove configure probes for sys/ipc.h, sys/sem.h, sys/shm.h.

  20. Remove configure probe for sys/resource.h and refactor.

  21. Remove configure probe for sys/uio.h.

  22. Fix obsolete comments in instr_time.h.

  23. aix: fix misreading of condition in 8f12a4e7add

  24. aix: Remove checks for very old OS versions

  25. windows: Remove HAVE_MINIDUMP_TYPE test

  26. solaris: Remove unnecessary gcc / gnu ld vs sun studio differences

  27. Trust a few system headers to stand on their own

  28. Rely on __func__ being supported

  29. Simplify replacement code for strtof.

  30. Simplify gettimeofday for Windows.

  31. Simplify gettimeofday() fallback logic.

  32. Remove fallbacks for strtoll, strtoull.

  33. Remove configure probe for fdatasync.

  34. Remove configure probe for clock_gettime.

  35. Simplify replacement code for preadv and pwritev.

  36. Remove dead pread and pwrite replacement code.

  37. Remove dead setenv, unsetenv replacement code.

  38. Remove configure probes for poll and poll.h.

  39. Remove configure probe for link.

  40. Remove configure probes for symlink/readlink, and dead code.

  41. Remove configure probe for setsid.

  42. Remove configure probe for shm_open.

  43. Remove configure probe and related tests for getrlimit.

  44. Remove configure probe for dlopen, and refactor.

  45. Remove dead getpwuid_r replacement code.

  46. Remove dead handling for pre-POSIX sigwait().

  47. Remove dead getrusage replacement code.

  48. Cygwin and Mingw floating-point fixes.

  49. Support platforms where strtoll/strtoull are spelled __strtoll/__strtoull.

  50. Arrange to supply declarations for strtoll/strtoull if needed.

  51. Lock down regression testing temporary clusters on Windows.

  52. Secure Unix-domain sockets of "make check" temporary clusters.

  53. Add configure checks for strtoll, strtoull (or strto[u]q). Disable

  54. Portability fix for old SunOS releases: fflush(NULL)