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7abc157165
Whenever this function is used with the FORMAT_MESSAGE_FROM_SYSTEM flag, it's good practice to include FORMAT_MESSAGE_IGNORE_INSERTS as well. Otherwise, if the message contains any %n insertion markers, the function will try to fetch argument strings to substitute --- which we are not passing, possibly leading to a crash. This is exactly analogous to the rule about not giving printf() a format string you're not in control of. Noted and patched by Christian Ullrich. Back-patch to all supported branches.
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 snprintf.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. Win32, Linux, and Darwin use an export list to
control the symbols exported by libpq.