diff --git a/Makefile b/Makefile
index 2858c6e..354654d 100644
--- a/Makefile
+++ b/Makefile
@@ -2,8 +2,10 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file. See the AUTHORS file for names of contributors.
 
+# Inherit some settings from environment variables, if available
 CXX ?= g++
 CC  ?= gcc
+INSTALL_PATH ?= $(CURDIR)
 
 #-----------------------------------------------
 # Uncomment exactly one of the lines labelled (A), (B), and (C) below
@@ -19,8 +21,8 @@ $(shell sh ./build_detect_platform)
 # this file is generated by build_detect_platform to set build flags and sources
 include build_config.mk
 
-CFLAGS += -c -I. -I./include $(PLATFORM_CCFLAGS) $(OPT)
-CXXFLAGS += -c -I. -I./include $(PLATFORM_CXXFLAGS) $(OPT)
+CFLAGS += -I. -I./include $(PLATFORM_CCFLAGS) $(OPT)
+CXXFLAGS += -I. -I./include $(PLATFORM_CXXFLAGS) $(OPT)
 
 LDFLAGS += $(PLATFORM_LDFLAGS)
 
@@ -55,15 +57,33 @@ BENCHMARKS = db_bench_sqlite3 db_bench_tree_db
 LIBRARY = libleveldb.a
 MEMENVLIBRARY = libmemenv.a
 
-all: $(LIBRARY)
+default: all
+
+# Should we build shared libraries?
+ifneq ($(PLATFORM_SHARED_EXT),)
+# Update db.h if you change these.
+SHARED_MAJOR = 1
+SHARED_MINOR = 3
+SHARED1 = libleveldb.$(PLATFORM_SHARED_EXT)
+SHARED2 = $(SHARED1).$(SHARED_MAJOR)
+SHARED3 = $(SHARED1).$(SHARED_MAJOR).$(SHARED_MINOR)
+SHARED = $(SHARED1) $(SHARED2) $(SHARED3)
+$(SHARED3):
+	$(CXX) $(LDFLAGS) $(PLATFORM_SHARED_LDFLAGS)$(INSTALL_PATH)/$(SHARED2) $(CXXFLAGS) $(PLATFORM_SHARED_CFLAGS) $(SOURCES) -o $(SHARED3)
+$(SHARED2): $(SHARED3)
+	ln -fs $(SHARED3) $(SHARED2)
+$(SHARED1): $(SHARED3)
+	ln -fs $(SHARED3) $(SHARED1)
+endif
+
+all: $(SHARED) $(LIBRARY)
 
-check: $(PROGRAMS) $(TESTS)
+check: all $(PROGRAMS) $(TESTS)
 	for t in $(TESTS); do echo "***** Running $$t"; ./$$t || exit 1; done
 
 clean:
-	-rm -f $(PROGRAMS) $(BENCHMARKS) $(LIBRARY) $(MEMENVLIBRARY) */*.o */*/*.o ios-x86/*/*.o ios-arm/*/*.o
+	-rm -f $(PROGRAMS) $(BENCHMARKS) $(LIBRARY) $(SHARED) $(MEMENVLIBRARY) */*.o */*/*.o ios-x86/*/*.o ios-arm/*/*.o build_config.mk
 	-rm -rf ios-x86/* ios-arm/*
-	-rm build_config.mk
 
 $(LIBRARY): $(LIBOBJECTS)
 	rm -f $@
@@ -142,22 +162,22 @@ IOSVERSION=$(shell defaults read /Developer/Platforms/iPhoneOS.platform/version
 
 .cc.o:
 	mkdir -p ios-x86/$(dir $@)
-	$(SIMULATORROOT)/usr/bin/$(CXX) $(CXXFLAGS) -isysroot $(SIMULATORROOT)/SDKs/iPhoneSimulator$(IOSVERSION).sdk -arch i686 $< -o ios-x86/$@
+	$(SIMULATORROOT)/usr/bin/$(CXX) $(CXXFLAGS) -isysroot $(SIMULATORROOT)/SDKs/iPhoneSimulator$(IOSVERSION).sdk -arch i686 -c $< -o ios-x86/$@
 	mkdir -p ios-arm/$(dir $@)
-	$(DEVICEROOT)/usr/bin/$(CXX) $(CXXFLAGS) -isysroot $(DEVICEROOT)/SDKs/iPhoneOS$(IOSVERSION).sdk -arch armv6 -arch armv7 $< -o ios-arm/$@
+	$(DEVICEROOT)/usr/bin/$(CXX) $(CXXFLAGS) -isysroot $(DEVICEROOT)/SDKs/iPhoneOS$(IOSVERSION).sdk -arch armv6 -arch armv7 -c $< -o ios-arm/$@
 	lipo ios-x86/$@ ios-arm/$@ -create -output $@
 
 .c.o:
 	mkdir -p ios-x86/$(dir $@)
-	$(SIMULATORROOT)/usr/bin/$(CC) $(CFLAGS) -isysroot $(SIMULATORROOT)/SDKs/iPhoneSimulator$(IOSVERSION).sdk -arch i686 $< -o ios-x86/$@
+	$(SIMULATORROOT)/usr/bin/$(CC) $(CFLAGS) -isysroot $(SIMULATORROOT)/SDKs/iPhoneSimulator$(IOSVERSION).sdk -arch i686 -c $< -o ios-x86/$@
 	mkdir -p ios-arm/$(dir $@)
-	$(DEVICEROOT)/usr/bin/$(CC) $(CFLAGS) -isysroot $(DEVICEROOT)/SDKs/iPhoneOS$(IOSVERSION).sdk -arch armv6 -arch armv7 $< -o ios-arm/$@
+	$(DEVICEROOT)/usr/bin/$(CC) $(CFLAGS) -isysroot $(DEVICEROOT)/SDKs/iPhoneOS$(IOSVERSION).sdk -arch armv6 -arch armv7 -c $< -o ios-arm/$@
 	lipo ios-x86/$@ ios-arm/$@ -create -output $@
 
 else
 .cc.o:
-	$(CXX) $(CXXFLAGS) $< -o $@
+	$(CXX) $(CXXFLAGS) -c $< -o $@
 
 .c.o:
-	$(CC) $(CFLAGS) $< -o $@
+	$(CC) $(CFLAGS) -c $< -o $@
 endif
diff --git a/build_detect_platform b/build_detect_platform
index df85264..64fcaef 100644
--- a/build_detect_platform
+++ b/build_detect_platform
@@ -5,6 +5,9 @@
 #
 # build_config.mk will set the following variables:
 #   PLATFORM_LDFLAGS            Linker flags
+#   PLATFORM_SHARED_EXT         Extension for shared libraries
+#   PLATFORM_SHARED_LDFLAGS     Flags for building shared library
+#   PLATFORM_SHARED_CFLAGS      Flags for compiling objects for shared library
 #   PLATFORM_CCFLAGS            C compiler flags
 #   PLATFORM_CXXFLAGS           C++ compiler flags.  Will contain:
 #       -DLEVELDB_PLATFORM_POSIX if cstdatomic is present
@@ -29,12 +32,17 @@ COMMON_FLAGS=
 PLATFORM_CCFLAGS=
 PLATFORM_CXXFLAGS=
 PLATFORM_LDFLAGS=
+PLATFORM_SHARED_EXT="so"
+PLATFORM_SHARED_LDFLAGS="-shared -Wl,-soname -Wl,"
+PLATFORM_SHARED_CFLAGS="-fPIC"
 
 # On GCC, we pick libc's memcmp over GCC's memcmp via -fno-builtin-memcmp
 case "$TARGET_OS" in
     Darwin)
         PLATFORM=OS_MACOSX
         COMMON_FLAGS="-fno-builtin-memcmp -DOS_MACOSX"
+        PLATFORM_SHARED_EXT=dylib
+        PLATFORM_SHARED_LDFLAGS="-dynamiclib -install_name "
         PORT_FILE=port/port_posix.cc
         ;;
     Linux)
@@ -143,3 +151,6 @@ echo "PLATFORM=$PLATFORM" >> build_config.mk
 echo "PLATFORM_LDFLAGS=$PLATFORM_LDFLAGS" >> build_config.mk
 echo "PLATFORM_CCFLAGS=$PLATFORM_CCFLAGS" >> build_config.mk
 echo "PLATFORM_CXXFLAGS=$PLATFORM_CXXFLAGS" >> build_config.mk
+echo "PLATFORM_SHARED_CFLAGS=$PLATFORM_SHARED_CFLAGS" >> build_config.mk
+echo "PLATFORM_SHARED_EXT=$PLATFORM_SHARED_EXT" >> build_config.mk
+echo "PLATFORM_SHARED_LDFLAGS=$PLATFORM_SHARED_LDFLAGS" >> build_config.mk
diff --git a/db/skiplist.h b/db/skiplist.h
index 0481575..af85be6 100644
--- a/db/skiplist.h
+++ b/db/skiplist.h
@@ -105,7 +105,8 @@ class SkipList {
   port::AtomicPointer max_height_;   // Height of the entire list
 
   inline int GetMaxHeight() const {
-    return reinterpret_cast<intptr_t>(max_height_.NoBarrier_Load());
+    return static_cast<int>(
+        reinterpret_cast<intptr_t>(max_height_.NoBarrier_Load()));
   }
 
   // Read/written only by Insert().
diff --git a/include/leveldb/db.h b/include/leveldb/db.h
index c1182b7..c7d5167 100644
--- a/include/leveldb/db.h
+++ b/include/leveldb/db.h
@@ -12,8 +12,9 @@
 
 namespace leveldb {
 
+// Update Makefile if you change these
 static const int kMajorVersion = 1;
-static const int kMinorVersion = 2;
+static const int kMinorVersion = 3;
 
 struct Options;
 struct ReadOptions;
diff --git a/include/leveldb/status.h b/include/leveldb/status.h
index 3355fac..11dbd4b 100644
--- a/include/leveldb/status.h
+++ b/include/leveldb/status.h
@@ -54,6 +54,12 @@ class Status {
   // Returns true iff the status indicates a NotFound error.
   bool IsNotFound() const { return code() == kNotFound; }
 
+  // Returns true iff the status indicates a Corruption error.
+  bool IsCorruption() const { return code() == kCorruption; }
+
+  // Returns true iff the status indicates an IOError.
+  bool IsIOError() const { return code() == kIOError; }
+
   // Return a string representation of this status suitable for printing.
   // Returns the string "OK" for success.
   std::string ToString() const;