Enable multithreading in lib build by default

Makefile

@@ -151,7 +151,6 @@ clean:
 ifneq (,$(filter $(shell uname),Linux Darwin GNU/kFreeBSD GNU OpenBSD FreeBSD DragonFly NetBSD MSYS_NT Haiku))
 
 HOST_OS = POSIX
-CMAKE_PARAMS = -DZSTD_BUILD_CONTRIB:BOOL=ON -DZSTD_BUILD_STATIC:BOOL=ON -DZSTD_BUILD_TESTS:BOOL=ON -DZSTD_ZLIB_SUPPORT:BOOL=ON -DZSTD_LZMA_SUPPORT:BOOL=ON -DCMAKE_BUILD_TYPE=Release
 
 HAVE_COLORNEVER = $(shell echo a | egrep --color=never a > /dev/null 2> /dev/null && echo 1 || echo 0)
 EGREP_OPTIONS ?=
@@ -357,6 +356,8 @@ lz4install:
 endif
 
 
+CMAKE_PARAMS = -DZSTD_BUILD_CONTRIB:BOOL=ON -DZSTD_BUILD_STATIC:BOOL=ON -DZSTD_BUILD_TESTS:BOOL=ON -DZSTD_ZLIB_SUPPORT:BOOL=ON -DZSTD_LZMA_SUPPORT:BOOL=ON -DZSTD_MULTITHREAD_SUPPORT:BOOL=ON -DCMAKE_BUILD_TYPE=Release
+
 ifneq (,$(filter MSYS%,$(shell uname)))
 HOST_OS = MSYS
 CMAKE_PARAMS = -G"MSYS Makefiles" -DCMAKE_BUILD_TYPE=Debug -DZSTD_MULTITHREAD_SUPPORT:BOOL=OFF -DZSTD_BUILD_STATIC:BOOL=ON -DZSTD_BUILD_TESTS:BOOL=ON

contrib/largeNbDicts/Makefile

@@ -23,6 +23,10 @@ DEBUGFLAGS= -Wall -Wextra -Wcast-qual -Wcast-align -Wshadow \
             -Wredundant-decls
 CFLAGS  += $(DEBUGFLAGS) $(MOREFLAGS)
 
+ifneq ($(ZSTD_NO_MULTITHREAD), 1)
+  CPPFLAGS += -DZSTD_MULTITHREAD
+  LDFLAGS  += -pthread
+endif
 
 default: largeNbDicts
 

contrib/seekable_format/examples/Makefile

@@ -18,6 +18,11 @@ CPPFLAGS += -I../ -I../../../lib -I../../../lib/common
 CFLAGS ?= -O3
 CFLAGS += -g
 
+ifneq ($(ZSTD_NO_MULTITHREAD), 1)
+  CPPFLAGS += -DZSTD_MULTITHREAD
+  LDFLAGS  += -pthread
+endif
+
 SEEKABLE_OBJS = ../zstdseek_compress.c ../zstdseek_decompress.c $(ZSTDLIB)
 
 .PHONY: default all clean test

contrib/seekable_format/tests/Makefile

@@ -19,6 +19,11 @@ CFLAGS ?= -O3
 CFLAGS += -g -Wall -Wextra -Wcast-qual -Wcast-align -Wconversion \
           -Wformat=2 -Wstrict-aliasing=1
 
+ifneq ($(ZSTD_NO_MULTITHREAD), 1)
+  CPPFLAGS += -DZSTD_MULTITHREAD
+  LDFLAGS  += -pthread
+endif
+
 SEEKABLE_OBJS = ../zstdseek_compress.c ../zstdseek_decompress.c $(ZSTDLIB)
 
 .PHONY: default clean test

lib/Makefile

@@ -32,6 +32,9 @@ LIBVER := $(shell echo $(LIBVER_SCRIPT))
 VERSION?= $(LIBVER)
 CCVER := $(shell $(CC) --version)
 
+# Multithreading can be forcibly disabled
+ZSTD_MULTITHREAD_MODE = 0
+
 # ZSTD_LIB_MINIFY is a helper variable that
 # configures a bunch of other variables to space-optimized defaults.
 ZSTD_LIB_MINIFY ?= 0
@@ -216,6 +219,22 @@ SET_CACHE_DIRECTORY = \
     CFLAGS="$(CFLAGS)" \
     LDFLAGS="$(LDFLAGS)"
 
+%-mt : ZSTD_MULTITHREAD_MODE=1 %
+	@echo multi-threading build completed
+
+%-nomt : ZSTD_MULTITHREAD_MODE=2
+%-nomt : %
+	@echo single-threaded build completed
+
+ZSTD_MULTITHREAD_MSG = single-threaded static lib, multi-threaded dynamic lib
+ifeq ($(ZSTD_MULTITHREAD_MODE), 1)
+  CPPFLAGS += -DZSTD_MULTITHREAD
+  LDFLAGS  += -pthread
+  ZSTD_MULTITHREAD_MSG = multi-threaded static and dynamic lib
+endif
+ifeq ($(ZSTD_MULTITHREAD_MODE), 2)
+  ZSTD_MULTITHREAD_MSG = single-threaded static and dynamic lib
+endif
 
 .PHONY: all
 all: lib
@@ -239,6 +258,7 @@ $(ZSTD_STATLIB): ARFLAGS = rcs
 $(ZSTD_STATLIB): | $(ZSTD_STATLIB_DIR)
 $(ZSTD_STATLIB): $(ZSTD_STATLIB_OBJ)
 	@echo compiling static library
+	@echo ZSTD_MULTITHREAD_MODE is $(ZSTD_MULTITHREAD_MODE)
 	$(AR) $(ARFLAGS) $@ $^
 
 libzstd.a: $(ZSTD_STATLIB)
@@ -269,6 +289,11 @@ $(LIBZSTD):
 else
 # BUILD_DIR is defined
 
+ifeq ($(ZSTD_MULTITHREAD_MODE), 0)
+  FLAGS += -DZSTD_MULTITHREAD
+  LDFLAGS  += -pthread
+endif
+
 ZSTD_DYNLIB_DIR := $(BUILD_DIR)/dynamic
 ZSTD_DYNLIB := $(ZSTD_DYNLIB_DIR)/$(LIBZSTD)
 ZSTD_DYNLIB_OBJ := $(addprefix $(ZSTD_DYNLIB_DIR)/,$(ZSTD_LOCAL_OBJ))
@@ -278,6 +303,7 @@ $(ZSTD_DYNLIB): $(ZSTD_DYNLIB_OBJ)
 	@echo compiling dynamic library $(LIBVER)
 	$(CC) $(FLAGS) $^ $(LDFLAGS) $(SONAME_FLAGS) -o $@
 	@echo creating versioned links
+	@echo ZSTD_MULTITHREAD_MODE is $(ZSTD_MULTITHREAD_MODE)
 	ln -sf $@ libzstd.$(SHARED_EXT_MAJOR)
 	ln -sf $@ libzstd.$(SHARED_EXT)
 
@@ -287,21 +313,17 @@ $(LIBZSTD): $(ZSTD_DYNLIB)
 endif  # ifndef BUILD_DIR
 endif  # if windows
 
+
 .PHONY: libzstd
 libzstd : $(LIBZSTD)
 
 .PHONY: lib
 lib : libzstd.a libzstd
+	@echo $(ZSTD_MULTITHREAD_MSG)
 
 
-# note : do not define lib-mt or lib-release as .PHONY
+# note : do not define lib-release as .PHONY
 # make does not consider implicit pattern rule for .PHONY target
-
-%-mt : CPPFLAGS += -DZSTD_MULTITHREAD
-%-mt : LDFLAGS  += -pthread
-%-mt : %
-	@echo multi-threading build completed
-
 %-release : DEBUGFLAGS :=
 %-release : %
 	@echo release build completed
@@ -332,11 +354,13 @@ include $(wildcard $(DEPFILES))
 # Special case : building library in single-thread mode _and_ without zstdmt_compress.c
 ZSTDMT_FILES = compress/zstdmt_compress.c
 ZSTD_NOMT_FILES = $(filter-out $(ZSTDMT_FILES),$(ZSTD_FILES))
+ZSTD_NOMT_FLAGS = $(filter-out -DZSTD_MULTITHREAD,$(FLAGS))
+ZSTD_NOMT_LDFLAGS = $(filter-out -pthread,$(LDFLAGS))
 libzstd-nomt: LDFLAGS += -shared -fPIC -fvisibility=hidden
 libzstd-nomt: $(ZSTD_NOMT_FILES)
 	@echo compiling single-thread dynamic library $(LIBVER)
 	@echo files : $(ZSTD_NOMT_FILES)
-	$(CC) $(FLAGS) $^ $(LDFLAGS) $(SONAME_FLAGS) -o $@
+	$(CC) $(ZSTD_NOMT_FLAGS) $^ $(ZSTD_NOMT_LDFLAGS) $(SONAME_FLAGS) -o $@
 
 .PHONY: clean
 clean:

lib/README.md

@@ -19,12 +19,16 @@ The scope can be reduced on demand (see paragraph _modular build_).
 
 #### Multithreading support
 
-Multithreading is disabled by default when building with `make`.
+When building with `make`, by default the dynamic library is multithreaded and static library is single-threaded (for compatibility reasons).
+
 Enabling multithreading requires 2 conditions :
 - set build macro `ZSTD_MULTITHREAD` (`-DZSTD_MULTITHREAD` for `gcc`)
 - for POSIX systems : compile with pthread (`-pthread` compilation flag for `gcc`)
 
-Both conditions are automatically applied when invoking `make lib-mt` target.
+For convenience, we provide a build target to generate multi and single threaded libraries:
+- Force enable multithreading on both dynamic and static libraries by appending `-mt` to the target, e.g. `make lib-mt`.
+- Force disable multithreading on both dynamic and static libraries by appending `-nomt` to the target, e.g. `make lib-nomt`.
+- And as mentioned before, dynamic library is multithreaded, and static library is single-threaded, e.g. `make lib`.
 
 When linking a POSIX program with a multithreaded version of `libzstd`,
 note that it's necessary to invoke the `-pthread` flag during link stage.

zlibWrapper/Makefile

@@ -20,6 +20,11 @@ TEST_FILE = ../doc/zstd_compression_format.md
 
 vpath %.c $(PROGRAMS_PATH) $(EXAMPLE_PATH) $(ZLIBWRAPPER_PATH)
 
+ZSTD_NO_MULTITHREAD ?= 0
+ifneq ($(ZSTD_NO_MULTITHREAD), 1)
+  CPPFLAGS += -DZSTD_MULTITHREAD
+  LDFLAGS  += -pthread
+endif
 
 CPPFLAGS += -DXXH_NAMESPACE=ZSTD_ -I$(ZLIB_PATH) -I$(PROGRAMS_PATH)       \
             -I$(ZSTDLIBDIR) -I$(ZSTDLIBDIR)/common -I$(ZLIBWRAPPER_PATH)