How to makefile

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发布于：Feb 26, 2020

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How to makefile

cheat sheet

Compile process

How dose a project turn into an excutable file? There are four step:

• Preprocessing
  • Unfold all include libs, macro, head. And produce .i file.
  • (gcc/g++ commands)-E
• Compilation
  • The .i file produce an .s file(assembly code).
  • -S
• Assemble
  • The .s file produce an .o file(object file).It is a binary file.
  • -c
• Linking
  • Linking the .o file produce an excutable file.

Whole example

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gcc -E halo.c -o halo.i  
gcc -S halo.i -o halo.s  
gcc -c halo.s -o halo.o  
gcc -o halo.o -o halo

Why makefile

As we see, compile a file include so much process.Though gcc halo.c -o halo can do the same thing as above, you need to make sure all the .c file are in the directory.
And what if a thousand file to compile?

Lets start

Format

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<target>: [dependencies]
<tab> [command]

^ before command IS A <TAB>, and make sure a new line at the end

We should write “from rear to front”. Which means write final target command first and then write dependencies commandS

[to remove] Usage

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make target...

If didn’t specify target, run the first target as default. That is why should we wirte main object at first.

Target

Prerequisites

Commands

Define

Grammar

Echoing

make will print out every single command that will execute

use @ to turn it off

Wildcard

Pattern matching

Variables

• $, $$
• =, :=, ?=, +=

Implicit Variables

handbook

Automatic Variables

• $@
• $<
• $?
• $^
• $*

handbook

Conditional

Functions

CMake

Makefile may not work at different platform. Is quite annoying to rebuild a Makefile. So CMake is came.

CMake can auto generate Makefile, it is more cross-platform.

Usually, cmake command write in a CMakeLists.txt file.

Some basic

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CMAKE_MINIMUM_REQUIRED(VERSION define_a_minimum_version_here)

PROJECT(define_project_name)

AUX_SOURCE_DIRECTORY(/your/dir/source pkg_name)  # to packaging files in dir_source. So you do not need every single source file below.

ADD_EXECUTABLE(executalbe_name source_files...)
# or
ADD_EXECUTABLE(executalbe_name ${pkg_name})

Multi Dir CMake

Every sub dir need a CMake file. So your main CMake file can use it.

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AUX_SOURCE_DIRECTORY(/your/dir/source pkg_name)

# static library
ADD_LIBRARY(lib_name STATIC ${pkg_name})  

# dynamic library
ADD_LIBRARY(lib_name SHARED ${pkg_name})

Use sub dir

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CMAKE_MINIMUM_REQUIRED(VERSION minimum_version)

PROJECT(project_name)

ADD_SUBDIRACTORY(./subdir)  # add subdir

AUX_SOURCE_DIRECTORY(/your/dir/source pkg_name)

ADD_EXECUTABLE(executalbe_name ${pkg_name})

TARGET_LINKLIBRARYS(executalbe_name SubLib)  # link sub lib

Standard Project

📁/Project
—📁/build
—📁/src
—📁/lib
—📝/CMakeLists.txt

• ./src/CMakeLists.txt

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  INCLUDE_DIRECTORY(./path/to/lib) #INCLUDE_DIRECTORY(./lib) SET(EXECUTABLE_OUTPUT_PATH $(PROJECT_BINARARY_DIR)/bin) # set executable output to EXECUTABLE_OUTPUT_PATH/bin =../build/bin AUX_SOURCE_DIRECTORY(/your/dir/source pkg_name) ADD_EXECUTABLE(executalbe_name ${pkg_name}) TARGET_LINKLIBRARYS(executalbe_name SubLib) # link sub lib

• ./lib/CMakeLists.txt

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  AUX_SOURCE_DIRECTORY(/your/dir/source pkg_name) SET(LIBRARAY_OUTPUT_PATH $(PROJECT_BINARARY_DIR)/lib) # set library output to PROJECT_BINARARY_DIR/lib=../build/lib # static library ADD_LIBRARY(lib_name STATIC ${pkg_name}) # dynamic library ADD_LIBRARY(lib_name SHARED ${pkg_name})

• ./CMakeLists.txt

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  CMAKE_MINIMUM_REQUIRED(VERSION minimum_version) PROJECT(project_name) ADD_SUBDIRACTORY(./subdir) # add subdir ADD_SUBDIRACTORY(./src)

• ccmake(config cmake)

• some other option