make

Original：🇺🇸 English

Translated

GNU Make skill for C/C++ build systems. Use when writing or debugging Makefiles, understanding pattern rules and automatic dependency generation, managing CFLAGS/LDFLAGS, converting ad-hoc compile commands into maintainable Makefiles, or diagnosing incremental build issues. Activates on queries about Makefiles, make targets, pattern rules, phony targets, dependency tracking, recursive make, or make errors.

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Sourcemohitmishra786/low-level-dev-skills

Added on2026-02-22

NPX Install

npx skill4agent add mohitmishra786/low-level-dev-skills make

SKILL.md Content

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GNU Make

Purpose

Guide agents through idiomatic Makefile patterns for C/C++ projects: phony targets, pattern rules, automatic dependency generation, and common build idioms.

Triggers

"How do I write a Makefile for my C project?"
"My Makefile rebuilds everything every time"
"How do I add dependency tracking to Make?"
"What does
```
$@
```
,
```
$<
```
,
```
$^
```
mean?"
"I'm getting 'make: Nothing to be done for all'"
"How do I convert my shell compile script to a Makefile?"

Workflow

1. Minimal correct Makefile for C

makefile

CC      := gcc
CFLAGS  := -std=c11 -Wall -Wextra -g -O2
LDFLAGS :=
LDLIBS  :=

SRCS    := $(wildcard src/*.c)
OBJS    := $(SRCS:src/%.c=build/%.o)
TARGET  := build/prog

.PHONY: all clean

all: $(TARGET)

$(TARGET): $(OBJS)
	$(CC) $(LDFLAGS) -o $@ $^ $(LDLIBS)

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

build:
	mkdir -p build

clean:
	rm -rf build

Automatic variables:

```
$@
```
— target name
```
$<
```
— first prerequisite
```
$^
```
— all prerequisites (deduplicated)
```
$*
```
— stem (the
```
%
```
part in a pattern rule)
```
$(@D)
```
— directory part of
```
$@
```

2. Automatic dependency generation

Without this, changing a header doesn't trigger a rebuild of

.c

files that include it.

makefile

CC      := gcc
CFLAGS  := -std=c11 -Wall -Wextra -g -O2
DEPFLAGS = -MMD -MP            # -MMD: generate .d file; -MP: phony targets for headers

SRCS    := $(wildcard src/*.c)
OBJS    := $(SRCS:src/%.c=build/%.o)
DEPS    := $(OBJS:.o=.d)
TARGET  := build/prog

.PHONY: all clean

all: $(TARGET)

$(TARGET): $(OBJS)
	$(CC) $(LDFLAGS) -o $@ $^ $(LDLIBS)

build/%.o: src/%.c | build
	$(CC) $(CFLAGS) $(DEPFLAGS) -MF $(@:.o=.d) -c -o $@ $<

-include $(DEPS)    # '-' ignores errors on first build (no .d files yet)

build:
	mkdir -p build

clean:
	rm -rf build

3. Pattern rules cheatsheet

makefile

# Compile C
%.o: %.c
	$(CC) $(CFLAGS) -c -o $@ $<

# Compile C++
%.o: %.cpp
	$(CXX) $(CXXFLAGS) -c -o $@ $<

# Generate assembly
%.s: %.c
	$(CC) $(CFLAGS) -S -o $@ $<

# Run a tool on each file
build/%.processed: src/%.raw | build
	mytool $< > $@

4. Common Make patterns

Debug and release builds

makefile

BUILD ?= release

ifeq ($(BUILD),debug)
  CFLAGS += -g -Og -DDEBUG
else
  CFLAGS += -O2 -DNDEBUG
endif

Usage:

make BUILD=debug

Parallel builds

bash

make -j$(nproc)     # use all CPUs
make -j4            # exactly 4 jobs

Add

-Otarget

(or

-O

) for ordered output:

make -j$(nproc) -O

Verbose output

makefile

# In Makefile: suppress with @
build/%.o: src/%.c | build
	@echo "  CC  $<"
	@$(CC) $(CFLAGS) -c -o $@ $<

Override silence:

make V=1

if you guard with

$(V)

:

makefile

Q := $(if $(V),,@)
build/%.o: src/%.c
	$(Q)$(CC) $(CFLAGS) -c -o $@ $<

Installing

makefile

PREFIX ?= /usr/local

install: $(TARGET)
	install -d $(DESTDIR)$(PREFIX)/bin
	install -m 0755 $(TARGET) $(DESTDIR)$(PREFIX)/bin/

5. Multi-directory projects

For medium projects, avoid recursive make (fragile, slow). Use a flat Makefile that includes sub-makefiles:

makefile

# project/Makefile
include lib/module.mk
include src/app.mk

makefile

# lib/module.mk
LIB_SRCS := $(wildcard lib/*.c)
LIB_OBJS := $(LIB_SRCS:lib/%.c=build/lib_%.o)
OBJS      += $(LIB_OBJS)

build/lib_%.o: lib/%.c
	$(CC) $(CFLAGS) -c -o $@ $<

6. Common errors

Error	Cause	Fix
`No rule to make target 'foo.o'`	Missing source or rule	Check source path and pattern rule
`Nothing to be done for 'all'`	Targets up to date	Touch a source file or run `make clean`
`Circular dependency dropped`	Target depends on itself	Check dependency chain
`missing separator`	Tab vs spaces	Recipes must use a tab, not spaces
`*** multiple target patterns`	Pattern rule syntax error	Check `%` placement
Rebuilds everything every time	Timestamps wrong, or PHONY missing	Check `date` ; ensure `all` is `.PHONY`
Header change not detected	No dep tracking	Add `-MMD -MP` and `-include $(DEPS)`

For a full variable and function reference, see references/cheatsheet.md.

Related skills

Use
```
skills/build-systems/cmake
```
for CMake-based projects
Use
```
skills/build-systems/ninja
```
for Ninja as a make backend
Use
```
skills/compilers/gcc
```
for CFLAGS details

make

NPX Install

Tags

SKILL.md Content

GNU Make

Purpose

Triggers

Workflow

1. Minimal correct Makefile for C

2. Automatic dependency generation

3. Pattern rules cheatsheet

4. Common Make patterns

Debug and release builds

Parallel builds

Verbose output

Installing

5. Multi-directory projects

6. Common errors

Related skills