x/sys: the IoctlSetPointerInt function should be available on macOS and BSD platforms

[krader1961]

Function unix.IoctlSetPointerInt should be available on all supported UNIX like systems.

I've been contributing to the Elvish shell project and recently attempted to replace it's custom Ioctl() function (because it had no unit tests) with functionality provided by golang.org/x/sys. However, one of the ioctl's Elvish uses is unix.TIOCSPGRP which requires using unix.IoctlSetPointerInt(). That transformation works fine on Linux but fails to build on macOS and FreeBSD with "undefined: unix.IoctlSetPointerInt". This is because unix.IoctlSetPointerInt is only implemented in syscall_linux.go. -- something that is not obvious from looking at the public documentation. I can't see any reason why this particular function can't be implemented generically for every UNIX like OS.

[gopherbot]

Change https://golang.org/cl/250001 mentions this issue: unix: make IoctlSetPointerInt available on all platforms

[tklauser]

Thanks, I think this makes sense to expose on all platforms and sent https://golang.org/cl/250001 with a fix.

Regarding the pkg.go.dev documentation: by default this is rendered for GOOS=linux, GOARCH=amd64 as indicated at the very bottom of the page, see https://pkg.go.dev/golang.org/x/sys@v0.0.0-20200821140526-fda516888d29/unix?tab=doc#XDPUmemReg:

Documentation was rendered with GOOS=linux and GOARCH=amd64.

FWIW, there is #37232 which requests support for different GOOS/GOARCH pairs on pkg.go.dev

[krader1961]

FWIW, I've confirmed the updated golang.org/x/sys package works for me on macOS, FreeBSD and Linux. Much thanks for the quick resolution.