How to Compile and Link Multiple .cpp Files into a Binary

This article aims to address the question of compiling multiple .cpp files into .o objects and linking them into a single binary.

Makefile Configuration

To accomplish this, a Makefile can be utilized with the following contents:

SRC_DIR = ./src
OBJ_DIR = ./obj
SRC_FILES = $(wildcard $(SRC_DIR)/*.cpp)
OBJ_FILES = $(patsubst $(SRC_DIR)/%.cpp,$(OBJ_DIR)/%.o,$(SRC_FILES))

main.exe: $(OBJ_FILES)
    g   $(LDFLAGS) -o $@ $^

$(OBJ_DIR)/%.o: $(SRC_DIR)/%.cpp
    g   $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $<

Explanation:

• SRC_DIR: Specifies the directory containing the source .cpp files.
• OBJ_DIR: Indicates the directory where the .o objects will be created.
• SRC_FILES: A list of all .cpp files in the SRC_DIR.
• OBJ_FILES: A list of all .o objects that will be generated.
• main.exe: The name of the final binary.
• LDFLAGS: Linker flags.
• CPPFLAGS: C preprocessor flags.
• CXXFLAGS: C compiler flags.

Dependency Graph Generation

To automatically generate dependencies between source and object files, add the following to the Makefile:

CXXFLAGS  = -MMD
-include $(OBJ_FILES:.o=.d)

Best Practices

This approach is commonly used for compiling and linking multiple C files. However, it's essential to refer to the GNU Make Manual for additional guidance and advanced options.