On: Why Use Make

[gcb0]

So what? you are doing it wrong.

there are lot's of people that use PHP for data crunching and bash for GUI and C without caring for managing memory properly.

should we retire all languages that can be abused?

also, your idea of how $ and $$ is wrong. but it could be that you messing up with = and := before that point :) so i guess your point stands. but again, all languages can be abused.

blame the bad coder, not the tool.

[ycombobreaker → gcb0]

> also, your idea of how $ and $$ is wrong

No, he's spot-on about that. If you are using a function from within a Makefile to generate Make code which then gets $(eval)ed, then then inner function must output $${variable} so that the outer function sees ${variable} and does not immediately resolve it.

It's hairy. Hairier than macros in C. But like any other specialization, it can potentially save an immense amount of time for the rest of the tam.

[SomeCallMeTim → gcb0]

> messing up with = and :=

Sorry, but I wasn't messing up those two. That's Makefile 101 knowledge; I'm talking about crazy advanced stuff, where := doesn't work the way you expect.

Even := doesn't do what you want if, after the Makefile has been loaded and you've used := three times on the same variable, ALL the instances of that variable are replaced by the last assignment. Here's an example:

    FOO:=1

    rule1 :
        echo $(FOO)

    FOO:=2

    rule2 :
        echo $(FOO)

make rule1 and make rule2 both echo 2. $(FOO) is evaluated in both cases AFTER the Makefile is loaded.

[sankl → SomeCallMeTim]

Target specific variables do this job:

    rule1 : FOO:=1
    rule1 :
        echo $(FOO)

    rule2 : FOO:=2
    rule2 :
        echo $(FOO)

[SomeCallMeTim → sankl]

Interesting. Didn't know this trick.

Turns out it wouldn't work for the usage pattern I needed (my example was simplified -- typically the variable settings would all happen in another file, and they couldn't happen on a target line because there wouldn't be a single target to use, in addition to just being ugly for that use), but it's good to know.