In commit 450ee7012 I supposed that all platforms we now care about have
snprintf(), since that's required by C99. Turns out that Microsoft did
not get around to adding that until VS2015. We've dropped support for
VS2013 as of HEAD (cf 6203583b7), but not in the back branches, so add
a hack for this in the back branches only.
There's no easy shortcut to an exact emulation of standard snprintf
in VS2013, but fortunately we don't need one: this code was just fine
with using sprintf before 450ee7012, so we can make it do so again
on that platform (and any others where the problem might crop up).
Per bug #17681 from Daisuke Higuchi. Back-patch to v12, like the
previous patch.
Discussion: https://postgr.es/m/17681-485ba2ec13e7f392@postgresql.org
src/port/README
libpgport
=========
libpgport must have special behavior. It supplies functions to both
libraries and applications. However, there are two complexities:
1) Libraries need to use object files that are compiled with exactly
the same flags as the library. libpgport might not use the same flags,
so it is necessary to recompile the object files for individual
libraries. This is done by removing -lpgport from the link line:
# Need to recompile any libpgport object files
LIBS := $(filter-out -lpgport, $(LIBS))
and adding infrastructure to recompile the object files:
OBJS= execute.o typename.o descriptor.o data.o error.o prepare.o memory.o \
connect.o misc.o path.o exec.o \
$(filter strlcat.o, $(LIBOBJS))
The problem is that there is no testing of which object files need to be
added, but missing functions usually show up when linking user
applications.
2) For applications, we use -lpgport before -lpq, so the static files
from libpgport are linked first. This avoids having applications
dependent on symbols that are _used_ by libpq, but not intended to be
exported by libpq. libpq's libpgport usage changes over time, so such a
dependency is a problem. Windows, Linux, AIX, and macOS use an export
list to control the symbols exported by libpq.
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