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by riking 1558 days ago
On many platforms, such as FreeBSD and macOS, the application-exposed ABI for tasks such as "open a file" or "validate this x.509 TLS certificate" mandates that you link to a shared library and call into it using the C calling convention. (libc and Security.framework, respectively.)

Linux is unique in that you can hand-write assembly to perform a system call and have it work across OS upgrades. FreeBSD does not have stable syscall numbers: open() must be a libc call.
1 comments
thatsnotc 1557 days ago
The application-exposed ABI for those tasks mandates that you execute a few assembly instructions to make a syscall (and perhaps also do some work that the libc normally wraps around the actual syscall for you). ABIs deal with machine instructions, that's why the "binary" is in there.

The OS-provided API for the tasks are libc and Security.framework. Do you have any suggestions for a better API?

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