Code change:
<ins> //! This is a regression test for #129020 //! It ensures we can use `/WHOLEARCHIVE` to link a rust staticlib into DLL //! using the MSVC linker //@ only-msvc // Reason: this is testing the MSVC linker use std::path::PathBuf; use run_make_support::{cc, cmd, env_var, extra_c_flags, rustc}; fn main() { // Build the staticlib rustc().crate_type("staticlib").input("static.rs").output("static.lib").run(); // Build an empty object to pass to the linker. cc().input("c.c").output("c.obj").args(["-c"]).run(); // Find the C toolchain's linker. let mut linker = PathBuf::from(env_var("CC")); let linker_flavour = if linker.file_stem().is_some_and(|s| s == "cl") { linker.set_file_name("link.exe"); "msvc" } else if linker.file_stem().is_some_and(|s| s == "clang-cl") { linker.set_file_name("lld-link.exe"); "llvm" } else { panic!("unknown C toolchain"); }; // As a sanity check, make sure this works without /WHOLEARCHIVE. // Otherwise the actual test failure may be caused by something else. cmd(&linker) .args(["c.obj", "./static.lib", "-dll", "-def:dll.def", "-out:dll.dll"]) .args(extra_c_flags()) .run(); // FIXME(@ChrisDenton): this doesn't currently work with llvm's lld-link for other reasons. // May need LLVM patches. if linker_flavour == "msvc" { // Link in the staticlib using `/WHOLEARCHIVE` and produce a DLL. cmd(&linker) .args([ "c.obj", "-WHOLEARCHIVE:./static.lib", "-dll", "-def:dll.def", "-out:dll_whole_archive.dll", ]) .args(extra_c_flags()) .run(); } } </ins>

Related discussion:
text: <!-- Thank you for filing a regression report! A regression is something that changed between versions of Rust but was not supposed to. Please provide a short summary of the regression, along with any information you feel is relevant to replicate it. --I tried to build using a simple then . I expected to see this happen: linking success. Instead, this happened: MSVC link returns LNK2005 and fails to the static library. It most recently worked on: 1.77.2 <!-- Provide the version you are using that has the regression. --: This is caused by both and When creating stdlibs, each MR causes the Rust compiler to add an export of ; one comes from api-ms-win-core-synch-l1-2-0.dll and the other from This error will not be found until one consumes the Rust-generated library. I am filing this report to consolidate the ones in and <!-- Did the compiler crash? If so, please provide a backtrace. --<!-- Include a backtrace in the code block by setting in your environment. E.g. . --<details<summaryBacktrace</summary<p</p</details modify labels: +regression-from-stable-to-stable -regression-untriaged
cc
Using for a rust staticlib seems weird to me but cc
The purpose is to allow reexporting a subset of symbols on MSVC. This can be achieved with partial linking elsewhere, but this is not doable on Windows. I wrote about a specific application here:
Sorry, I'm confused, are you trying to create a dynamic or static library? The article that you linked to talks about static libraries, but the backtrace in the OP shows that you are creating a dynamic library.
Both: I'm using the Rust-produced static library through , plus a module definition file, to create a dynamic library. This is because (apart from size considerations) GNOME's gobject-introspection needs a shared library, and Meson will only accept targets that are generated by itself. Further context is here:
In this particular case, because of the imports present in the stdlib, linking something against the Rust-produced static librsvg is enough to trigger the issue.
I am still struggling to understand why is needed, at least for MSVC.