Comment by jart

We're pretty much on the same page. I'm not sure if I share your enthusiasm for clone(), but I think the canonical Linux interface is what's going to save us from the dark patterns we see in userspace. I think everyone should learn how to use raw system calls. Because the first thought that's going to cross their mind is "wow I thought my C library was doing all these things" and then they're going to want a C library that offers more value than putting a number in the eax register.

For example if you want to call fork() using asm() then on Linux it's simple:

    int fork(void) {
      int ax;
      asm volatile("syscall" : "=a"(ax) : "0"(57) : "rcx", "r11", "memory", "cc");
      if (ax > -4096) errno = -ax, ax = -1;
      return ax;
    }

But if you want to support XNU, FreeBSD, OpenBSD, FreeBSD, and NetBSD too, it gets a little trickier:

    int fork(void) {
      char cf;
      int ax, dx;
      ax = IsLinux() ? 57 : 2;
      if (IsXnu()) ax |= 0x2000000;
      asm volatile("clc\n\t"
                   "syscall"
                   : "+a"(ax), "=d"(dx), "=@ccc"(cf)
                   : "1"(0)
                   : "rcx", "r11", "memory", "cc");
      if (cf) ax = -ax;
      if (ax > -4096) errno = -ax, ax = -1;
      if (ax != -1) ax &= dx - 1;
      return ax;
    }

Cosmopolitan abstracts stuff like that for you, but right now that's only if you're the kind of person who doesn't need threads. I imagine you are, since folks who do smart things with multiprocessing models like Go and Chromium usually don't want C libraries potentially stepping on their toes. Oh gosh threads. The day I figure out how to do those, will be day the whole world will want to use this thing. But I want people who use Cosmopolitan Libc to know what value it's providing them. I think the best way to do that is by raising awareness of the systems engineering fundamentals like this. Because that's something you're right to point out that the Linux community leadership has room for improvement on.