diff --git a/src/include/port.h b/src/include/port.h
index 6bcb8ae7e81..3692cdbbc54 100644
--- a/src/include/port.h
+++ b/src/include/port.h
@@ -148,12 +148,11 @@ extern int	pg_strncasecmp(const char *s1, const char *s2, size_t n);
 extern unsigned char pg_toupper(unsigned char ch);
 extern unsigned char pg_tolower(unsigned char ch);
 
-#ifdef USE_REPL_SNPRINTF
-
 /*
- * Versions of libintl >= 0.13 try to replace printf() and friends with
- * macros to their own versions that understand the %$ format.  We do the
- * same, so disable their macros, if they exist.
+ * Capture macro-compatible calls to printf() and friends, and redirect them
+ * to wrappers that throw errors in lieu of reporting failure in a return
+ * value.  Versions of libintl >= 0.13 similarly redirect to versions that
+ * understand the %$ format, so disable libintl macros first.
  */
 #ifdef vsnprintf
 #undef vsnprintf
@@ -177,6 +176,55 @@ extern unsigned char pg_tolower(unsigned char ch);
 #undef printf
 #endif
 
+extern int
+vsnprintf_throw_on_fail(char *str, size_t count, const char *fmt, va_list args)
+__attribute__((format(printf, 3, 0)));
+extern int
+snprintf_throw_on_fail(char *str, size_t count, const char *fmt,...)
+__attribute__((format(printf, 3, 4)));
+extern int
+vsprintf_throw_on_fail(char *str, const char *fmt, va_list args)
+__attribute__((format(printf, 2, 0)));
+extern int
+sprintf_throw_on_fail(char *str, const char *fmt,...)
+__attribute__((format(printf, 2, 3)));
+extern int
+vfprintf_throw_on_fail(FILE *stream, const char *fmt, va_list args)
+__attribute__((format(printf, 2, 0)));
+extern int
+fprintf_throw_on_fail(FILE *stream, const char *fmt,...)
+__attribute__((format(printf, 2, 3)));
+extern int
+printf_throw_on_fail(const char *fmt,...)
+__attribute__((format(printf, 1, 2)));
+
+/*
+ *	The GCC-specific code below prevents the __attribute__(... 'printf')
+ *	above from being replaced, and this is required because gcc doesn't
+ *	know anything about printf_throw_on_fail.
+ */
+#ifdef __GNUC__
+#define vsnprintf(...)	vsnprintf_throw_on_fail(__VA_ARGS__)
+#define snprintf(...)	snprintf_throw_on_fail(__VA_ARGS__)
+#define vsprintf(...)	vsprintf_throw_on_fail(__VA_ARGS__)
+#define sprintf(...)	sprintf_throw_on_fail(__VA_ARGS__)
+#define vfprintf(...)	vfprintf_throw_on_fail(__VA_ARGS__)
+#define fprintf(...)	fprintf_throw_on_fail(__VA_ARGS__)
+#define printf(...)		printf_throw_on_fail(__VA_ARGS__)
+#else
+#define vsnprintf		vsnprintf_throw_on_fail
+#define snprintf		snprintf_throw_on_fail
+#define vsprintf		vsprintf_throw_on_fail
+#define sprintf			sprintf_throw_on_fail
+#define vfprintf		vfprintf_throw_on_fail
+#define fprintf			fprintf_throw_on_fail
+#define printf			printf_throw_on_fail
+#endif
+
+#ifdef USE_REPL_SNPRINTF
+
+/* Code outside syswrap.c should not call these. */
+
 extern int	pg_vsnprintf(char *str, size_t count, const char *fmt, va_list args);
 extern int
 pg_snprintf(char *str, size_t count, const char *fmt,...)
@@ -197,28 +245,6 @@ pg_printf(const char *fmt,...)
 /* This extension allows gcc to check the format string */
 __attribute__((format(printf, 1, 2)));
 
-/*
- *	The GCC-specific code below prevents the __attribute__(... 'printf')
- *	above from being replaced, and this is required because gcc doesn't
- *	know anything about pg_printf.
- */
-#ifdef __GNUC__
-#define vsnprintf(...)	pg_vsnprintf(__VA_ARGS__)
-#define snprintf(...)	pg_snprintf(__VA_ARGS__)
-#define vsprintf(...)	pg_vsprintf(__VA_ARGS__)
-#define sprintf(...)	pg_sprintf(__VA_ARGS__)
-#define vfprintf(...)	pg_vfprintf(__VA_ARGS__)
-#define fprintf(...)	pg_fprintf(__VA_ARGS__)
-#define printf(...)		pg_printf(__VA_ARGS__)
-#else
-#define vsnprintf		pg_vsnprintf
-#define snprintf		pg_snprintf
-#define vsprintf		pg_vsprintf
-#define sprintf			pg_sprintf
-#define vfprintf		pg_vfprintf
-#define fprintf			pg_fprintf
-#define printf			pg_printf
-#endif
 #endif   /* USE_REPL_SNPRINTF */
 
 /*
diff --git a/src/interfaces/ecpg/compatlib/Makefile b/src/interfaces/ecpg/compatlib/Makefile
index 45c8f9462f4..481059f4bc8 100644
--- a/src/interfaces/ecpg/compatlib/Makefile
+++ b/src/interfaces/ecpg/compatlib/Makefile
@@ -36,6 +36,7 @@ all: all-lib
 # Shared library stuff
 include $(top_srcdir)/src/Makefile.shlib
 
+# XXX This library uses no symbols from snprintf.c.
 snprintf.c: % : $(top_srcdir)/src/port/%
 	rm -f $@ && $(LN_S) $< .
 
diff --git a/src/interfaces/ecpg/ecpglib/.gitignore b/src/interfaces/ecpg/ecpglib/.gitignore
index e6c60b16fcd..f3513db90c1 100644
--- a/src/interfaces/ecpg/ecpglib/.gitignore
+++ b/src/interfaces/ecpg/ecpglib/.gitignore
@@ -6,4 +6,5 @@
 /path.c
 /pgstrcasecmp.c
 /strlcpy.c
+/syswrap.c
 /thread.c
diff --git a/src/interfaces/ecpg/ecpglib/Makefile b/src/interfaces/ecpg/ecpglib/Makefile
index 46693896bbb..50e0b0650c6 100644
--- a/src/interfaces/ecpg/ecpglib/Makefile
+++ b/src/interfaces/ecpg/ecpglib/Makefile
@@ -25,7 +25,7 @@ override CFLAGS += $(PTHREAD_CFLAGS)
 LIBS := $(filter-out -lpgport, $(LIBS))
 
 OBJS= execute.o typename.o descriptor.o sqlda.o data.o error.o prepare.o memory.o \
-	connect.o misc.o path.o pgstrcasecmp.o \
+	connect.o misc.o path.o pgstrcasecmp.o syswrap.o \
 	$(filter snprintf.o strlcpy.o isinf.o, $(LIBOBJS))
 
 # thread.c is needed only for non-WIN32 implementation of path.c
@@ -58,7 +58,7 @@ include $(top_srcdir)/src/Makefile.shlib
 # necessarily use the same object files as the backend uses. Instead,
 # symlink the source files in here and build our own object file.
 
-path.c pgstrcasecmp.c snprintf.c strlcpy.c thread.c isinf.c: % : $(top_srcdir)/src/port/%
+path.c pgstrcasecmp.c snprintf.c strlcpy.c syswrap.c thread.c isinf.c: % : $(top_srcdir)/src/port/%
 	rm -f $@ && $(LN_S) $< .
 
 misc.o: misc.c $(top_builddir)/src/port/pg_config_paths.h
@@ -75,6 +75,6 @@ uninstall: uninstall-lib
 
 clean distclean: clean-lib
 	rm -f $(OBJS)
-	rm -f path.c pgstrcasecmp.c snprintf.c strlcpy.c thread.c
+	rm -f path.c pgstrcasecmp.c snprintf.c strlcpy.c syswrap.c thread.c
 
 maintainer-clean: distclean maintainer-clean-lib
diff --git a/src/interfaces/ecpg/pgtypeslib/.gitignore b/src/interfaces/ecpg/pgtypeslib/.gitignore
index aa5bdb837f2..83f896c7a7a 100644
--- a/src/interfaces/ecpg/pgtypeslib/.gitignore
+++ b/src/interfaces/ecpg/pgtypeslib/.gitignore
@@ -4,3 +4,4 @@
 /exports.list
 
 /pgstrcasecmp.c
+/syswrap.c
diff --git a/src/interfaces/ecpg/pgtypeslib/Makefile b/src/interfaces/ecpg/pgtypeslib/Makefile
index 7f71e1bc5cc..69b8c832508 100644
--- a/src/interfaces/ecpg/pgtypeslib/Makefile
+++ b/src/interfaces/ecpg/pgtypeslib/Makefile
@@ -29,7 +29,7 @@ SHLIB_LINK += -lm
 SHLIB_EXPORTS = exports.txt
 
 OBJS= numeric.o datetime.o common.o dt_common.o timestamp.o interval.o \
-	pgstrcasecmp.o \
+	pgstrcasecmp.o syswrap.o \
 	$(filter rint.o snprintf.o, $(LIBOBJS))
 
 all: all-lib
@@ -42,7 +42,7 @@ include $(top_srcdir)/src/Makefile.shlib
 # necessarily use the same object files as the backend uses. Instead,
 # symlink the source files in here and build our own object file.
 
-pgstrcasecmp.c rint.c snprintf.c: % : $(top_srcdir)/src/port/%
+pgstrcasecmp.c rint.c snprintf.c syswrap.c: % : $(top_srcdir)/src/port/%
 	rm -f $@ && $(LN_S) $< .
 
 install: all installdirs install-lib
@@ -52,6 +52,6 @@ installdirs: installdirs-lib
 uninstall: uninstall-lib
 
 clean distclean: clean-lib
-	rm -f $(OBJS) pgstrcasecmp.c rint.c snprintf.c
+	rm -f $(OBJS) pgstrcasecmp.c rint.c snprintf.c syswrap.c
 
 maintainer-clean: distclean maintainer-clean-lib
diff --git a/src/interfaces/libpq/.gitignore b/src/interfaces/libpq/.gitignore
index f086ec3db7e..1be81ec6588 100644
--- a/src/interfaces/libpq/.gitignore
+++ b/src/interfaces/libpq/.gitignore
@@ -8,6 +8,7 @@
 /snprintf.c
 /strerror.c
 /strlcpy.c
+/syswrap.c
 /thread.c
 /win32error.c
 /pgsleep.c
diff --git a/src/interfaces/libpq/Makefile b/src/interfaces/libpq/Makefile
index 98d9e8164f2..74f10662baf 100644
--- a/src/interfaces/libpq/Makefile
+++ b/src/interfaces/libpq/Makefile
@@ -33,7 +33,7 @@ LIBS := $(LIBS:-lpgport=)
 OBJS=	fe-auth.o fe-connect.o fe-exec.o fe-misc.o fe-print.o fe-lobj.o \
 	fe-protocol2.o fe-protocol3.o pqexpbuffer.o pqsignal.o fe-secure.o \
 	libpq-events.o \
-	md5.o ip.o wchar.o encnames.o noblock.o pgstrcasecmp.o thread.o \
+	md5.o ip.o wchar.o encnames.o noblock.o pgstrcasecmp.o syswrap.o thread.o \
 	$(filter crypt.o getaddrinfo.o inet_aton.o open.o snprintf.o strerror.o strlcpy.o win32error.o, $(LIBOBJS))
 
 ifeq ($(PORTNAME), cygwin)
@@ -80,7 +80,7 @@ backend_src = $(top_srcdir)/src/backend
 # For port modules, this only happens if configure decides the module
 # is needed (see filter hack in OBJS, above).
 
-crypt.c getaddrinfo.c inet_aton.c noblock.c open.c pgstrcasecmp.c snprintf.c strerror.c strlcpy.c thread.c win32error.c pgsleep.c: % : $(top_srcdir)/src/port/%
+crypt.c getaddrinfo.c inet_aton.c noblock.c open.c pgstrcasecmp.c snprintf.c strerror.c strlcpy.c syswrap.c thread.c win32error.c pgsleep.c: % : $(top_srcdir)/src/port/%
 	rm -f $@ && $(LN_S) $< .
 
 md5.c ip.c: % : $(backend_src)/libpq/%
@@ -133,7 +133,7 @@ ifneq (,$(findstring $(PORTNAME), win32 cygwin))
 endif
 
 clean distclean: clean-lib
-	rm -f $(OBJS) pg_config_paths.h crypt.c getaddrinfo.c inet_aton.c noblock.c open.c pgstrcasecmp.c snprintf.c strerror.c strlcpy.c thread.c md5.c ip.c encnames.c wchar.c win32error.c pgsleep.c pthread.h libpq.rc
+	rm -f $(OBJS) pg_config_paths.h crypt.c getaddrinfo.c inet_aton.c noblock.c open.c pgstrcasecmp.c snprintf.c strerror.c strlcpy.c syswrap.c thread.c md5.c ip.c encnames.c wchar.c win32error.c pgsleep.c pthread.h libpq.rc
 # Might be left over from a Win32 client-only build
 	rm -f pg_config_paths.h
 
diff --git a/src/interfaces/libpq/bcc32.mak b/src/interfaces/libpq/bcc32.mak
index f109f27a365..4152ff85533 100644
--- a/src/interfaces/libpq/bcc32.mak
+++ b/src/interfaces/libpq/bcc32.mak
@@ -104,6 +104,7 @@ CLEAN :
 	-@erase "$(INTDIR)\dirmod.obj"
 	-@erase "$(INTDIR)\pgsleep.obj"
 	-@erase "$(INTDIR)\open.obj"
+	-@erase "$(INTDIR)\syswrap.obj"
 	-@erase "$(INTDIR)\win32error.obj"
 	-@erase "$(OUTDIR)\$(OUTFILENAME).lib"
 	-@erase "$(OUTDIR)\$(OUTFILENAME)dll.lib"
@@ -145,6 +146,7 @@ LIB32_OBJS= \
 	"$(INTDIR)\dirmod.obj" \
 	"$(INTDIR)\pgsleep.obj" \
 	"$(INTDIR)\open.obj" \
+	"$(INTDIR)\syswrap.obj" \
 	"$(INTDIR)\win32error.obj" \
 	"$(INTDIR)\pthread-win32.obj"
 
@@ -273,6 +275,11 @@ LINK32_FLAGS = -Gn -L$(BCB)\lib;$(INTDIR); -x -Tpd -v
 	$(CPP_PROJ) /I"." ..\..\port\open.c
 <<
 
+"$(INTDIR)\syswrap.obj" : ..\..\port\syswrap.c
+	$(CPP) @<<
+	$(CPP_PROJ) ..\..\port\syswrap.c
+<<
+
 "$(INTDIR)\win32error.obj" : ..\..\port\win32error.c
 	$(CPP) @<<
 	$(CPP_PROJ) /I"." ..\..\port\win32error.c
diff --git a/src/interfaces/libpq/win32.mak b/src/interfaces/libpq/win32.mak
index 56b24a5cdce..e075051f042 100644
--- a/src/interfaces/libpq/win32.mak
+++ b/src/interfaces/libpq/win32.mak
@@ -111,6 +111,7 @@ CLEAN :
 	-@erase "$(INTDIR)\dirmod.obj"
 	-@erase "$(INTDIR)\pgsleep.obj"
 	-@erase "$(INTDIR)\open.obj"
+	-@erase "$(INTDIR)\syswrap.obj"
 	-@erase "$(INTDIR)\win32error.obj"
 	-@erase "$(OUTDIR)\$(OUTFILENAME).lib"
 	-@erase "$(OUTDIR)\$(OUTFILENAME)dll.lib"
@@ -154,6 +155,7 @@ LIB32_OBJS= \
 	"$(INTDIR)\dirmod.obj" \
 	"$(INTDIR)\pgsleep.obj" \
 	"$(INTDIR)\open.obj" \
+	"$(INTDIR)\syswrap.obj" \
 	"$(INTDIR)\win32error.obj" \
 	"$(INTDIR)\pthread-win32.obj"
 
@@ -311,6 +313,11 @@ LINK32_OBJS= \
 	$(CPP_PROJ) /I"." ..\..\port\open.c
 <<
 
+"$(INTDIR)\syswrap.obj" : ..\..\port\syswrap.c
+	$(CPP) @<<
+	$(CPP_PROJ) ..\..\port\syswrap.c
+<<
+
 "$(INTDIR)\win32error.obj" : ..\..\port\win32error.c
 	$(CPP) @<<
 	$(CPP_PROJ) /I"." ..\..\port\win32error.c
diff --git a/src/port/Makefile b/src/port/Makefile
index 8589108f55c..c7000ba9a61 100644
--- a/src/port/Makefile
+++ b/src/port/Makefile
@@ -31,7 +31,7 @@ override CPPFLAGS := -I$(top_builddir)/src/port -DFRONTEND $(CPPFLAGS)
 LIBS += $(PTHREAD_LIBS)
 
 OBJS = $(LIBOBJS) chklocale.o dirmod.o exec.o noblock.o path.o \
-	pgsleep.o pgstrcasecmp.o qsort.o qsort_arg.o sprompt.o thread.o
+	pgsleep.o pgstrcasecmp.o qsort.o qsort_arg.o sprompt.o syswrap.o thread.o
 ifneq (,$(filter $(PORTNAME),cygwin win32))
 OBJS += pipe.o
 endif
diff --git a/src/port/snprintf.c b/src/port/snprintf.c
index 1fd91a36e8f..281bba169e6 100644
--- a/src/port/snprintf.c
+++ b/src/port/snprintf.c
@@ -114,6 +114,7 @@ typedef struct
 	/* bufend == NULL is for sprintf, where we assume buf is big enough */
 	FILE	   *stream;			/* eventual output destination, or NULL */
 	int			nchars;			/* # chars already sent to stream */
+	bool		failed;			/* call is a failure; errno is set */
 }	PrintfTarget;
 
 /*
@@ -143,7 +144,7 @@ typedef union
 
 
 static void flushbuffer(PrintfTarget * target);
-static int	dopr(PrintfTarget * target, const char *format, va_list args);
+static void dopr(PrintfTarget * target, const char *format, va_list args);
 
 
 int
@@ -157,14 +158,10 @@ pg_vsnprintf(char *str, size_t count, const char *fmt, va_list args)
 	target.bufend = str + count - 1;
 	target.stream = NULL;
 	/* target.nchars is unused in this case */
-	if (dopr(&target, fmt, args))
-	{
-		*(target.bufptr) = '\0';
-		errno = EINVAL;			/* bad format */
-		return -1;
-	}
+	target.failed = false;
+	dopr(&target, fmt, args);
 	*(target.bufptr) = '\0';
-	return target.bufptr - target.bufstart;
+	return target.failed ? -1 : (target.bufptr - target.bufstart);
 }
 
 int
@@ -190,14 +187,10 @@ pg_vsprintf(char *str, const char *fmt, va_list args)
 	target.bufend = NULL;
 	target.stream = NULL;
 	/* target.nchars is unused in this case */
-	if (dopr(&target, fmt, args))
-	{
-		*(target.bufptr) = '\0';
-		errno = EINVAL;			/* bad format */
-		return -1;
-	}
+	target.failed = false;
+	dopr(&target, fmt, args);
 	*(target.bufptr) = '\0';
-	return target.bufptr - target.bufstart;
+	return target.failed ? -1 : (target.bufptr - target.bufstart);
 }
 
 int
@@ -227,14 +220,11 @@ pg_vfprintf(FILE *stream, const char *fmt, va_list args)
 	target.bufend = buffer + sizeof(buffer) - 1;
 	target.stream = stream;
 	target.nchars = 0;
-	if (dopr(&target, fmt, args))
-	{
-		errno = EINVAL;			/* bad format */
-		return -1;
-	}
+	target.failed = false;
+	dopr(&target, fmt, args);
 	/* dump any remaining buffer contents */
 	flushbuffer(&target);
-	return target.nchars;
+	return target.failed ? -1 : target.nchars;
 }
 
 int
@@ -261,14 +251,24 @@ pg_printf(const char *fmt,...)
 	return len;
 }
 
-/* call this only when stream is defined */
+/*
+ * Attempt to write the entire buffer to target->stream; discard the entire
+ * buffer in any case.  Call this only when target->stream is defined.
+ */
 static void
 flushbuffer(PrintfTarget * target)
 {
 	size_t		nc = target->bufptr - target->bufstart;
 
-	if (nc > 0)
-		target->nchars += fwrite(target->bufstart, 1, nc, target->stream);
+	if (!target->failed && nc > 0)
+	{
+		size_t		written;
+
+		written = fwrite(target->bufstart, 1, nc, target->stream);
+		target->nchars += written;
+		if (written != nc)
+			target->failed = true;
+	}
 	target->bufptr = target->bufstart;
 }
 
@@ -295,7 +295,7 @@ static void trailing_pad(int *padlen, PrintfTarget * target);
 /*
  * dopr(): poor man's version of doprintf
  */
-static int
+static void
 dopr(PrintfTarget * target, const char *format, va_list args)
 {
 	const char *format_start = format;
@@ -372,12 +372,12 @@ nextch1:
 			case '$':
 				have_dollar = true;
 				if (accum <= 0 || accum > NL_ARGMAX)
-					return -1;
+					goto bad_format;
 				if (afterstar)
 				{
 					if (argtypes[accum] &&
 						argtypes[accum] != ATYPE_INT)
-						return -1;
+						goto bad_format;
 					argtypes[accum] = ATYPE_INT;
 					last_dollar = Max(last_dollar, accum);
 					afterstar = false;
@@ -414,7 +414,7 @@ nextch1:
 						atype = ATYPE_INT;
 					if (argtypes[fmtpos] &&
 						argtypes[fmtpos] != atype)
-						return -1;
+						goto bad_format;
 					argtypes[fmtpos] = atype;
 					last_dollar = Max(last_dollar, fmtpos);
 				}
@@ -426,7 +426,7 @@ nextch1:
 				{
 					if (argtypes[fmtpos] &&
 						argtypes[fmtpos] != ATYPE_INT)
-						return -1;
+						goto bad_format;
 					argtypes[fmtpos] = ATYPE_INT;
 					last_dollar = Max(last_dollar, fmtpos);
 				}
@@ -439,7 +439,7 @@ nextch1:
 				{
 					if (argtypes[fmtpos] &&
 						argtypes[fmtpos] != ATYPE_CHARPTR)
-						return -1;
+						goto bad_format;
 					argtypes[fmtpos] = ATYPE_CHARPTR;
 					last_dollar = Max(last_dollar, fmtpos);
 				}
@@ -455,7 +455,7 @@ nextch1:
 				{
 					if (argtypes[fmtpos] &&
 						argtypes[fmtpos] != ATYPE_DOUBLE)
-						return -1;
+						goto bad_format;
 					argtypes[fmtpos] = ATYPE_DOUBLE;
 					last_dollar = Max(last_dollar, fmtpos);
 				}
@@ -476,7 +476,7 @@ nextch1:
 
 	/* Per spec, you use either all dollar or all not. */
 	if (have_dollar && have_non_dollar)
-		return -1;
+		goto bad_format;
 
 	/*
 	 * In dollar mode, collect the arguments in physical order.
@@ -486,7 +486,7 @@ nextch1:
 		switch (argtypes[i])
 		{
 			case ATYPE_NONE:
-				return -1;		/* invalid format */
+				goto bad_format;
 			case ATYPE_INT:
 				argvalues[i].i = va_arg(args, int);
 				break;
@@ -511,6 +511,9 @@ nextch1:
 	format = format_start;
 	while ((ch = *format++) != '\0')
 	{
+		if (target->failed)
+			break;
+
 		if (ch != '%')
 		{
 			dopr_outch(ch, target);
@@ -755,7 +758,11 @@ nextch2:
 		}
 	}
 
-	return 0;
+	return;
+
+bad_format:
+	errno = EINVAL;
+	target->failed = true;
 }
 
 static size_t
@@ -805,8 +812,10 @@ fmtptr(void *value, PrintfTarget * target)
 
 	/* we rely on regular C library's sprintf to do the basic conversion */
 	vallen = sprintf(convert, "%p", value);
-
-	dostr(convert, vallen, target);
+	if (vallen < 0)
+		target->failed = true;
+	else
+		dostr(convert, vallen, target);
 }
 
 static void
@@ -939,16 +948,19 @@ fmtfloat(double value, char type, int forcesign, int leftjust,
 
 	if (pointflag)
 	{
-		sprintf(fmt, "%%.%d%c", prec, type);
+		if (sprintf(fmt, "%%.%d%c", prec, type) < 0)
+			goto fail;
 		zeropadlen = precision - prec;
 	}
-	else
-		sprintf(fmt, "%%%c", type);
+	else if (sprintf(fmt, "%%%c", type) < 0)
+		goto fail;
 
 	if (!isnan(value) && adjust_sign((value < 0), forcesign, &signvalue))
 		value = -value;
 
 	vallen = sprintf(convert, fmt, value);
+	if (vallen < 0)
+		goto fail;
 
 	/* If it's infinity or NaN, forget about doing any zero-padding */
 	if (zeropadlen > 0 && !isdigit((unsigned char) convert[vallen - 1]))
@@ -988,6 +1000,10 @@ fmtfloat(double value, char type, int forcesign, int leftjust,
 	}
 
 	trailing_pad(&padlen, target);
+	return;
+
+fail:
+	target->failed = true;
 }
 
 static void
diff --git a/src/port/syswrap.c b/src/port/syswrap.c
new file mode 100644
index 00000000000..8415a336303
--- /dev/null
+++ b/src/port/syswrap.c
@@ -0,0 +1,155 @@
+/*-------------------------------------------------------------------------
+ *
+ * syswrap.c
+ *	  error-throwing wrappers around POSIX functions that rarely fail
+ *
+ * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
+ *
+ *
+ * IDENTIFICATION
+ *	  src/port/syswrap.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#ifndef FRONTEND
+#include "postgres.h"
+#else
+#include "postgres_fe.h"
+#endif
+
+/* Prevent recursion */
+#undef	vsnprintf
+#undef	snprintf
+#undef	vsprintf
+#undef	sprintf
+#undef	vfprintf
+#undef	fprintf
+#undef	printf
+
+/* When the libc primitives are lacking, use our own. */
+#ifdef USE_REPL_SNPRINTF
+#ifdef __GNUC__
+#define vsnprintf(...)	pg_vsnprintf(__VA_ARGS__)
+#define snprintf(...)	pg_snprintf(__VA_ARGS__)
+#define vsprintf(...)	pg_vsprintf(__VA_ARGS__)
+#define sprintf(...)	pg_sprintf(__VA_ARGS__)
+#define vfprintf(...)	pg_vfprintf(__VA_ARGS__)
+#define fprintf(...)	pg_fprintf(__VA_ARGS__)
+#define printf(...)		pg_printf(__VA_ARGS__)
+#else
+#define vsnprintf		pg_vsnprintf
+#define snprintf		pg_snprintf
+#define vsprintf		pg_vsprintf
+#define sprintf			pg_sprintf
+#define vfprintf		pg_vfprintf
+#define fprintf			pg_fprintf
+#define printf			pg_printf
+#endif
+#endif   /* USE_REPL_SNPRINTF */
+
+/*
+ * We abort() in the frontend, rather than exit(), because libpq in particular
+ * has no business calling exit().  These failures had better be rare.
+ */
+#ifdef FRONTEND
+#define LIB_ERR(func) \
+do { \
+	int discard = fprintf(stderr, "%s failed: %s\n", func, strerror(errno)); \
+	(void) discard; \
+	abort(); \
+} while (0)
+#else
+#define LIB_ERR(func) elog(ERROR, "%s failed: %m", func)
+#endif
+
+int
+vsnprintf_throw_on_fail(char *str, size_t count, const char *fmt, va_list args)
+{
+	int			save_errno;
+	int			ret;
+
+	/*
+	 * On HP-UX B.11.31, a call that truncates output returns -1 without
+	 * setting errno.  (SUSv2 allowed this until the approval of Base Working
+	 * Group Resolution BWG98-006.)  We could avoid the save and restore of
+	 * errno on most platforms.
+	 */
+	save_errno = errno;
+	errno = 0;
+	ret = vsnprintf(str, count, fmt, args);
+	if (ret < 0 && errno != 0)
+		LIB_ERR("vsnprintf");
+	errno = save_errno;
+	return ret;
+}
+
+int
+snprintf_throw_on_fail(char *str, size_t count, const char *fmt,...)
+{
+	int			ret;
+	va_list		args;
+
+	va_start(args, fmt);
+	ret = vsnprintf_throw_on_fail(str, count, fmt, args);
+	va_end(args);
+	return ret;
+}
+
+int
+vsprintf_throw_on_fail(char *str, const char *fmt, va_list args)
+{
+	int			ret;
+
+	ret = vsprintf(str, fmt, args);
+	if (ret < 0)
+		LIB_ERR("vsprintf");
+	return ret;
+}
+
+int
+sprintf_throw_on_fail(char *str, const char *fmt,...)
+{
+	int			ret;
+	va_list		args;
+
+	va_start(args, fmt);
+	ret = vsprintf_throw_on_fail(str, fmt, args);
+	va_end(args);
+	return ret;
+}
+
+int
+vfprintf_throw_on_fail(FILE *stream, const char *fmt, va_list args)
+{
+	int			ret;
+
+	ret = vfprintf(stream, fmt, args);
+	if (ret < 0)
+		LIB_ERR("vfprintf");
+	return ret;
+}
+
+int
+fprintf_throw_on_fail(FILE *stream, const char *fmt,...)
+{
+	int			ret;
+	va_list		args;
+
+	va_start(args, fmt);
+	ret = vfprintf_throw_on_fail(stream, fmt, args);
+	va_end(args);
+	return ret;
+}
+
+int
+printf_throw_on_fail(const char *fmt,...)
+{
+	int			ret;
+	va_list		args;
+
+	va_start(args, fmt);
+	ret = vfprintf_throw_on_fail(stdout, fmt, args);
+	va_end(args);
+	return ret;
+}
diff --git a/src/tools/msvc/Mkvcbuild.pm b/src/tools/msvc/Mkvcbuild.pm
index fa97c79471d..d1bbedc8bc2 100644
--- a/src/tools/msvc/Mkvcbuild.pm
+++ b/src/tools/msvc/Mkvcbuild.pm
@@ -52,7 +52,7 @@ sub mkvcbuild
       chklocale.c crypt.c fseeko.c getrusage.c inet_aton.c random.c srandom.c
       getaddrinfo.c gettimeofday.c kill.c open.c erand48.c mkdtemp.c
       snprintf.c strlcat.c strlcpy.c dirmod.c exec.c noblock.c path.c pipe.c
-      pgsleep.c pgstrcasecmp.c qsort.c qsort_arg.c sprompt.c thread.c
+      pgsleep.c pgstrcasecmp.c qsort.c qsort_arg.c sprompt.c syswrap.c thread.c
       getopt.c getopt_long.c dirent.c rint.c win32env.c win32error.c);
 
     $libpgport = $solution->AddProject('libpgport','lib','misc');