Prevent espacing " in configureFlags

I want to pass multiple flags to configure inside a string like this:

--with-spral-lflags="-lspral -lgfortran -lhwloc -lm -lcoinmetis -lopenblas -lstdc++ -fopenmp"

but if I add it to configureFlags as

''--with-spral-lflags="-lspral -lgfortran -lhwloc -lm -lcoinmetis -lopenblas -lstdc++ -fopenmp"''

or by using " and escaping it it results in

--with-spral-lflags=\"-lspral -lgfortran -lhwloc -lm -lcoinmetis -lopenblas -lstdc++ -fopenmp\"

Is there a way to prevent this, or is there a better way to achieve this?

In my config files I escape those characters with '' a double single quote.

There are two different escape sequences in nix, depending on which type of string you use: Data Types - Nix Reference Manual

You’re currently using the wrong escape for ''.

That said, you shouldn’t need to escape " in a '' string. If you end up with spurious backslashes something else is wrong.

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You probably have to use configFlagsArray. It is mentioned at Nixpkgs 23.11 manual | Nix & NixOS.

The similar makeFlagsArray has a usage example at Nixpkgs 23.11 manual | Nix & NixOS

You need of course to stay within preConfigure or “earlier”.


That’s what I was missing, ty!

I knew I was missing something, but as searched for the wrong keyword.

It looks like this now for me:

preConfigure = ''
    "--with-spral-lflags=-lspral -lgfortran -lhwloc -lm -lmetis -lopenblas -lstdc++ -fopenmp"