This is really great resource, didn't know about it. But one question not related to the website above - why the syscalls vary per architecture if the linux API is the same?

Or is it I am confusing it with the C standard library/POSIX and assuming that it should be the same everywhere?

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guitmz 7 hours ago | parent [-]

The Linux kernel API is the same everywhere, but the syscall ABI (numbers, calling convention, entry paths) is specific to a architecture, while it's the C library that wraps those details into the portable POSIX API we code against

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weli 7 hours ago | parent | next [-]

Also newer archs (riscv) don't support certain syscalls (open, fork) they are still functions you can call under your standard musl,glibc but they inernally call openat, clone.

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tomtomtom777 6 hours ago | parent | prev [-]

I see, but why were they numbered differently? Why not use the same numbers?

	▲	guitmz 6 hours ago \| parent [-]
		As far as I know, the numbers were assigned independently by each port's developers in the 90s as they added calls in their own order. Then it became a frozen ABI nobody could ever renumber, and couldn't have been identical anyway since arches need different syscall variants for things like 32bit vs 64bit types