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alexcrichton / curl-rust

Rust bindings to libcurl
MIT License
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Add an environment variable for requesting static linking with libcurl #319

Closed dmitmel closed 4 years ago

dmitmel commented 4 years ago

Based on the exact same feature of libz-sys implemented here:

https://github.com/rust-lang/libz-sys/blob/510d1b6a8935d7de974a0bfb4d9764bae28bb474/build.rs#L24-L25

This is necessary to enabled/disable static linking based on the target platform, since Cargo doesn't support target-specific features for dependencies.

Also, since curl-sys depends on libz-sys, I think it would be also useful to make a feature called static-libz which enables the static feature in libz-sys. I can implement this in another PR.

alexcrichton commented 4 years ago

Thanks for the PR! I feel like though there's already such a myriad of ways to link to libcurl that I'd prefer to not add yet another way to configure this. Rationalizing with all the existing ways feels like it's just unnecessarily complicating things :(

dmitmel commented 4 years ago

The problem is basically what I described - there is no way right now to enable static linking based on the target platform. This is useful when building cross platform applications - you'd want to reuse system libcurl on *NIXes (macOS, Linux etc) and link statically on Windows because it doesn't provide libcurl.

Also, IMO I'm not proposing a new way of linking, instead I'm proposing a new way of enabling static linking (which is an existing way), in other words effect of CURL_SYS_STATIC is equivalent to enabling the feature static-curl.

alexcrichton commented 4 years ago

Yes I realize it's another way of doing things but that's sort of just it, it's a new way of doing things on top of the litany of "things" that are already there. There's already so many options of how curl can be configured, and I'm hesitant to just keep adding whatever someone thinks of as a new possible option. Eventually this sort of configuration will end up collapsing under it's own weight.

dmitmel commented 4 years ago

Okay then, but please help me in this case. I'm currently developing an application which uses curl to make HTTP requests (unsurprisingly). Windows doesn't provide libcurl, so for Windows static linking is required. macOS has a new enough version of libcurl in its default installation, so I'd like to reuse that. Also, AFAIK most Linux distributions recommend dynamically linking to make use of libraries installed via a package manager. Now here is the question: how would you implement this sort of platform-dependent static linking on the application level if you were me?

alexcrichton commented 4 years ago

I'm sorry for the delay on getting back to this. I'm also sorry but I don't have a ton of time right now to help out with this. I don't have the energy myself to keep maintaining such a long list of ways to link to libcurl in this crate, so I'm going to stick to what's here for now. I'm sorry if it doesn't solve your use case at this time, but I don't have a better solution :(

dmitmel commented 4 years ago

Nevermind. I implemented this by doing the following:

https://github.com/CCDirectLink/ccloader-installer/blob/4ccf6dc29804967235ae386609ca01dc3367ce33/Cargo.toml#L45-L48