Added `install` and `uninstall` targets. Added documentation to Makefile

Fortune for sink's current commit: Blessing − 吉

Makefile

@@ -1,32 +1,58 @@
-# Sinks all input to /dev/null
+# `sink` - sinks all input to /dev/null
+#
+# Targets:
+# `sink` (default): stripped `release` target. output: `sink`
+# `release`: optimised build. output: `sink-release`
+# `debug`: unoptimised build with debuginfo. output: `sink-debug`
+# `clean`: remove all previous object and binary output files
+#
+# Environment variables:
+# * `SHARED` - set to "yes" to prevent passing `--static` to cc
+# * `TARGET_ARCH` - target arch (`-march=`), or set `TARGET_ARCH=` to force set to generic target. (default [release only]: `native`)
+# * `CFLAGS`, `COMMON_FLAGS` - passthrough to cc
+# * `LDFLAGS` - passthrough to ld
+# * `DEBUG_CFLAGS`, `DEBUG_LDFLAGS` - passthrough to cc / ld on target `debug`
+# * `RELEASE_CFLAGS`, `RELEASE_LDFLAGS` - passthrough to cc / ld on target `release`
+#
+# Make overridable only:
+# * `STRIP` - Strip command for default output (stripped release) target (`make sink`). set `make STRIP=:` to prevent stripping entirely. (NOTE: When using `make install`, `STRIP=:` will not work, instead, paradoxically, set `STRIP=true`, they have the same effect for all targets)
 PROJECT=sink
 
 SRC=$(wildcard *.c)
 OUTPUT=$(PROJECT)
 
+ifeq ($(PREFIX),)
+	PREFIX := /usr/local
+endif
+
 COMMON_FLAGS+= -W -Wall -Wextra -Wstrict-aliasing -fno-strict-aliasing
 
 TARGET_ARCH?=native
 ifneq ($(TARGET_ARCH),)
 	TARGET_ARCH:=$(addprefix -march=,$(TARGET_ARCH))
 endif
-RELEASE_CFLAGS+= $(TARGET_ARCH) -fgraphite -fopenmp -floop-parallelize-all -ftree-parallelize-loops=4 \
+RELEASE_CFLAGS+= $(TARGET_ARCH) -fgraphite \
 	    -floop-interchange -ftree-loop-distribution -floop-strip-mine -floop-block \
 	    -fno-stack-check
 
-RELEASE_CFLAGS+= -O3 -flto
+RELEASE_CFLAGS+= -O3 -flto -DRELEASE
 RELEASE_LDFLAGS+= -Wl,-O3 -Wl,-flto
 
-DEBUG_CFLAGS+=-Og -g3 -ggdb -gz
+DEBUG_CFLAGS+=-Og -g3 -ggdb -gz -DDEBUG
 DEBUG_LDFLASG+=-Wl,-g
 
 CFLAGS   += $(COMMON_FLAGS) --std=gnu17
 LDFLAGS  +=
 
+ifneq ($(SHARED),yes)
+	CFLAGS+=--static
+endif
+
 OBJ   = $(SRC:.c=.o)
 
 STRIP=strip
 
+
 # Phonies
 
 .PHONY: $(OUTPUT)
@@ -62,4 +88,10 @@ clean:
 	rm -f $(OUTPUT) $(PROJECT)-*
 
 
+.PHONY: install
+install: 
+	install -s --strip-program=$(STRIP) -m 755 $(OUTPUT) $(DESTDIR)$(PREFIX)/bin
 
+.PHONY: uninstall
+uninstall:
+	rm -f $(DESTDIR)$(PREFIX)/bin/$(OUTPUT)

sink.c

@@ -6,8 +6,8 @@
 #define r_stdout 1
 #define r_stderr 2
 
-#define LIKELY(e) __builtin_expect(!!(e), 1)
-#define UNLIKELY(e) __builtin_expect(!!(e), 0)
+#define LIKELY(e) __builtin_expect((e) != 0, 1)
+#define UNLIKELY(e) __builtin_expect((e) != 0, 0)
 
 static inline int dupall(int from)
 {
@@ -39,5 +39,8 @@ int main(void)
 		perror("failed to open /dev/null");
 		return 1;
 	}
-	return dupall(null);
+	register int rc = dupall(null);
+	if(LIKELY(rc)) close(null);
+	return rc;
 }
+