Makefile Pattern Rules & Dependency Generation

%.o: %.c
  cc -c $< -o $@

# Compile any `.c` file into a matching `.o` file.

build/%.o: src/%.c
  mkdir -p $(dir $@)
  cc -c $< -o $@

# Build objects into a separate output directory.

objects := main.o util.o api.o

$(objects): %.o: %.c
  cc -c $< -o $@

# Apply a pattern to a known target list.

SRC := $(wildcard src/*.c)
OBJ := $(patsubst src/%.c,build/%.o,$(SRC))

# Create object names from source names.

app: $(OBJ)
  cc $(OBJ) -o $@

# Assemble final executable from all objects.

.SUFFIXES:

# Reduce surprises by disabling legacy suffix rules.

archive.tar.gz: dist
  tar -czf $@ dist

# Expand to the current target file.

%.o: %.c
  cc -c $< -o $@

# Expand to the first prerequisite.

app: main.o util.o
  cc $^ -o $@

# Expand to all prerequisites without duplicates.

libfoo.a: foo.o bar.o
  ar rcs $@ $?

# Expand to prerequisites newer than the target.

build/%.min.js: src/%.js
  terser $< -o build/$*.min.js

# Use the matched stem from the target pattern.

copy:
  @echo dir=$(dir $@) file=$(notdir $@)

# Extract target directory or file name.

SRC := $(wildcard src/**/*.ts)

# Expand glob patterns during parsing.

UNIQ_SRC := $(sort $(SRC))

# Sort and deduplicate a list of words.

TESTS := $(filter %_test.py,$(FILES))

# Keep only values that match a pattern.

SRC_NO_VENDOR := $(filter-out vendor/%,$(SRC))

# Exclude matches from a list.

PKG_TARGETS := $(foreach p,$(PACKAGES),test-$(p))

# Generate text for each item in a list.

CFLAGS += -MMD -MP

build/%.o: src/%.c
  cc $(CFLAGS) -c $< -o $@

-include $(OBJ:.o=.d)

# Have the compiler emit `.d` files while building objects.

build/%.o: src/%.c
  cc -MMD -MP -MF build/$*.d -c $< -o $@

# Write depfiles beside objects using explicit flags.

node_modules/.stamp: package-lock.json
  npm ci
  touch $@

build: node_modules/.stamp

# Rebuild only when lockfile changes.

-include $(DEPS)

# Load dependency files only if they exist.

libfoo.a: $(OBJ)
  ar rcs $@ $^

# Create an archive from object files.

libfoo.a: $(OBJ)
  ar rcs $@ $?

# Use `$?` to add only changed prerequisites.