Fails when Swift C++ interop is turned on

[aDifferentJT]

The generated C headers do not include guards to add extern "C" if compiled as C++, which means that I had to turn off Swift C++ interop, which is a shame. It'd be nice if we added these into the generated headers to enable C++ compatibility.

#ifdef __cplusplus
extern "C" {
#endif

#ifdef __cplusplus
}
#endif

[chinedufn]

Thank you for the report.

I haven't used Swift/C++ interop before, so I'd like to better understand what our options are for supporting it.

Is your proposed solution the only solution, or are there others? What are you using Swift / C++ interop for (just so I can better understand the needs that we're serving here and can be confident that we are serving them well).

Would your proposed solution make Swift/C++ support fully work for everyone, or is it a quick hack that just works for some basic use cases?

I can do more research as well, but first I'd appreciate a better sense of what exactly you're trying to do and why what you've proposed is the best (or only) way to do it.

Are there any downsides or tradeoffs with swift-bridge supporting Swift / C++ interop?

I haven't read the cxx-interop page yet, but when I search "#ifdef" nothing comes up, which makes me curious about whether this is necessary or if there are alternative paths to enabling Swift / C++ interop https://www.swift.org/documentation/cxx-interop/
How did you arrive at your proposed #ifdef directive solution?

[aDifferentJT]

When you turn on Swift/C++ interop the bridging header is parsed as a C++ header.

This is just the standard way to make a header that works as both C and C++, it's not a swift specific thing, surrounding the declarations with extern "C" { } is requires to ensure that the C++ compiler recognises that these functions should be compiled with C linkage, not C++.
The ifdefs are there to prevent a C only compiler from getting confused.

This is an old and fairly common trick, you can see it described by the ISO C++ FAQ (https://isocpp.org/wiki/faq/mixing-c-and-cpp#include-c-hdrs-personal)

This isn't about making swift-bridge support C++ interop, so much as preventing swift-bridge from breaking when used in a project that enables Swift/C++ interop (for instance, in order to interface separately with a totally separate library).

[aDifferentJT]

I did try adding the extern "C" { } guards around my #include, however this fails because the #include <stdint.h> and #include <stdbool.h> do not expect to be surrounded by extern "C" { }, which is why it is necessary for swift-bridge to emit them.