How to Set Default Link Flags for GHC?

#1

Hey there! I’m just getting into Haskell and I’m trying to get the compiler working, but I’m having an issue.

I’m on Linux and I have my gmp library installed to ~/.local/lib because I’m not root on my machine and can’t install system packages.

I can compile a hello world program if I run ghc -L$HOME/.local/lib hello.hs, but I want to add -L$HOME/.local/lib as a default linker argument so that I don’t have to pass it in every time I compile a haskell program.

Are there any environment variables or configurations I can set to add global linker flags?

It looks like haskell packages have a way to add linker flags, so maybe I can make a dummy package that adds to the linker search path, and then just install it?

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#2

You can edit the C compiler link flags line in $(ghc --print-libdir)/settings and add the -L flag there. (or set the CONF_GCC_LINKER_OPTS_STAGE2 environment envariable to your linker flag when installing ghc)

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#3

That worked great, thanks! :+1:

I didn’t see anything about a settings dir in the GHC User Guide. Did I just miss it, or should that be added. I could maybe open a PR.

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#4

Knowledge about the settings file is better suited in the GHC commentary IMO, given it’s purely an internal implementation detail. Ironically I failed to find such a wiki page, it makes sense to create a page for it though, in the future it may be gradually populated by explanations of individual settings fields.

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#5

There you go, created a new page for it:

I mentioned the ld flags setting, and a note that I didn’t know when that was used instead of the c compiler link flags. I’m not sure what the best tense to use when indicating something I’m unsure of in the docs.

It might be better to avoid the I pronoun for a doc that could have multiple authors.

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