69ae9dcb44
It's important for link commands to list *.o input files before -l switches for libraries, as library code may not get pulled into the link unless referenced by an earlier command-line entry. This is certainly necessary for static libraries (.a style). Apparently on some platforms it is also necessary for shared libraries, as reported by Donald Dong. We often put -l switches for within-tree libraries into LDFLAGS, meaning that link commands that list *.o files after LDFLAGS are hazardous. Most of our link commands got this right, but a few did not. In particular, places that relied on gmake's default implicit link rule failed, because that puts LDFLAGS first. Fix that by overriding the built-in rule with our own. The implicit link rules in src/makefiles/Makefile.* for single-.o-file shared libraries mostly got this wrong too, so fix them. I also changed the link rules for the backend and a couple of other places for consistency, even though they are not (currently) at risk because they aren't adding any -l switches to LDFLAGS. Arguably, the real problem here is that we're abusing LDFLAGS by putting -l switches in it and we should stop doing that. But changing that would be quite invasive, so I'm not eager to do so. Perhaps this is a candidate for back-patching, but so far it seems that problems can only be exhibited in test code we don't normally build, and at least some of the problems are new in HEAD anyway. So I'll refrain for now. Donald Dong and Tom Lane Discussion: https://postgr.es/m/CAKABAquXn-BF-vBeRZxhzvPyfMqgGuc74p8BmQZyCFDpyROBJQ@mail.gmail.com |
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| Makefile | ||
| README | ||
| thread_test.c | ||
README
src/test/thread/README
Threading
=========
This program is run by configure to determine if threading is
properly supported on the platform.
You can run the program manually to see details, which shows if your
native libc functions are thread-safe, or if we use *_r functions or
thread locking.
To use this program manually, you must:
o run "configure"
o compile the main source tree
o compile and run this program
If your platform requires special thread flags that are not tested by
/config/acx_pthread.m4, add PTHREAD_CFLAGS and PTHREAD_LIBS defines to
your template/${port} file.
Windows Systems
===============
Windows systems do not vary in their thread-safeness in the same way that
other systems might, nor do they generally have pthreads installed, hence
on Windows this test is skipped by the configure program (pthreads is
required by the test program, but not PostgreSQL itself). If you do wish
to test your system however, you can do so as follows:
1) Install pthreads in you Mingw/Msys environment. You can download pthreads
from ftp://sources.redhat.com/pub/pthreads-win32/.
2) Build the test program:
gcc -o thread_test.exe \
-D_REENTRANT \
-D_THREAD_SAFE \
-D_POSIX_PTHREAD_SEMANTICS \
-I../../../src/include/port/win32 \
thread_test.c \
-lws2_32 \
-lpthreadgc2
3) Run thread_test.exe. You should see output like:
dpage@PC30:/cvs/pgsql/src/tools/thread$ ./thread_test
Your GetLastError() is thread-safe.
Your system uses strerror() which is thread-safe.
getpwuid_r()/getpwuid() are not applicable to Win32 platforms.
Your system uses gethostbyname which is thread-safe.
Your platform is thread-safe.