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Comment by yjftsjthsd-h

5 days ago

> First of all, it is the OS ABI, in operating systems that happened to be written in C.

It may be per-OS (I wouldn't try linking Linux and NT object files even if they were both compiled from C by GCC with matching versions and everything), but enough details come from C that I think it's fair to call it a C ABI. Like, I can write unix software in pascal, but in order to write to stdout that code is gonna have to convert pascal strings into C strings. OTOH, pascal binaries using pascal libraries can use pascal semantics even on an OS that uses C ABIs.

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yjftsjthsd-h

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pjmlp  5 days ago

Strings is the easy part.

Try to link two binary libraries in Linux, both compiled with GCC, while not using exactly the same compiler flags, or the same data padding, for example things like structures.

Since committee people can explain it even better,

"To Save C, We Must Save ABI"

https://thephd.dev/to-save-c-we-must-save-abi-fixing-c-funct...

  • uecker  5 days ago

    Sorry, this is nonsense. Binaries link just fine on Linux. If you use a compiler flag that changes the ABI, then you are on your own, of course, but the GCC docu makes it very clear which specific flags those are. There is some corner cases with problems where you get problems if you use different compilers, e.g. atomic alignment (by adopting the broken C++ design into C) and some other corner cases where compilers did things slightly different.