Good Makefiles (2018)

hoytech 7 years ago |

You shouldn't hard-code gcc. make has an implicit CC variable for this: https://www.gnu.org/software/make/manual/html_node/Implicit-...

Your makefile will then work on systems without gcc, and it is also easier to override it, ie:

    make CC=clang

flukus 7 years ago | |

> You shouldn't hard-code gcc.

You should unless you've committed to writing portable code. If you're using GCC specific features then using CC would imply a false level of compatibility.

In this case they are using gcc specific features "-MMD -MP -MT".

hoytech 7 years ago | | |

I just tested and this Makefile works fine with clang, except that -flto should be added to LDFLAGS.

In fact I believe it should be there for gcc too, according to https://gcc.gnu.org/wiki/LinkTimeOptimization so perhaps this is a bug in the Makefile?

Flushing out issues like this is another reason to commit to writing portable code (and build systems), as you put it.

jdmoreira 7 years ago | |

or just rely on the /usr/bin/cc symbolic link

ohithereyou 7 years ago | | |

Not every system that can use Makefiles has a C compiler at /usr/bin/cc

jdmoreira 7 years ago | | |

we shouldn't hardcode the path but I would assume that most unixes with a C compiler will have a cc symlinked somewhere in the $PATH

ohithereyou 7 years ago | | |

Okay, and what if someone wants to cross-compile?

pletnes 7 years ago |

Make is a great tool. I mostly use it to remember repetitive tasks, like running python tests, not as a build system. Works even better for this. What annoys me deeply is that gnu make isn’t available on windows, e.g git bash.

okl 7 years ago | |

The one fatal flaw is it's inability to handle whitespace in paths. How do you avoid that problem?

ashton314 7 years ago | | |

Can you give us an example?

okl 7 years ago | | |

http://savannah.gnu.org/bugs/?712

Trufa 7 years ago |

I really don't know the first thing about C or makefiles o anything related, but I was browsing the code out of general curiosity and I have a question.

Would this code benefit from better variable names or is it just that I don't know the domain and this is good understandable code? I'm honestly curious.

This happens a lot with C code examples here.

mmphosis 7 years ago | |

I think that most code benefits from better variable names. For ease of typing and for historical reasons, abbreviated variable names are in the C and makefile domain:

BIN = BINary executable

SRCS = SouRCe fileS

OBJS = OBJect fileS

DEPS = DEPendency fileS

CFLAGS = C compiler FLAGS passed as arguments to the C compiler

LDFLAGS = linker or Link eDitor FLAGS passed as arguments to the linker

okl 7 years ago | |

I would say that the variable naming in the linked Makefile follows the usual conventions. Sure it could benefit - but at the cost of confusing readers who are accustomed to those conventions.

Retra 7 years ago | |

Most of the variables here have standard names that show up in most makefiles.

dang 7 years ago |

There's a larger discussion on this topic at https://news.ycombinator.com/item?id=19052830.

oso2k 7 years ago |

For lots of things, and especially if you stick to the Unix Philosophy or Suckless Philosophy, this Makefile is all you need. I personally add ‘install’, ‘uninstall’, ‘clean’, and ‘superclean’ targets to my projects but this is a really great start.

jdc 7 years ago |

I understand there's lots of build systems out there with better scripting languages, but is there anything else that can challenge make for simplicity and portability (although I guess you could export Makefiles)?

okl 7 years ago | |

What about CMake?

jdc 7 years ago | | |

Right, CMake seems like a more than adequate replacement. Then it becomes a question of why so many people are still writing Makefiles by hand.

Kenji 7 years ago |

Unfortunately, the reality is never as simple as that. Your makefile will grow like a tumour once your project grows: Specific dependencies, OS and compiler related flags and switches, special folder structures, etc etc.

damota 7 years ago |

It's a terrible Makefile