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Comment by aidenn0 | Hacker News Reader

This author talks about POSIX as if a bunch of people sat down and invented a portable OS API. The reality is closer to: a group of people at AT&T created Unix, a number of other companies and universities modified Unix, and then people sat down and said "how can we unify the APIs of the fragmented Unix world"

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The Programming API layer is fragmented in the UNIX world. There's mostly only ANSI C, X, and gcc, which exist everywhere, but it's still not trivial to port between *NIX. The kernel API is the most useless fragmentation of them all. It's addressed by POSIX and UDI (http://www.project-udi.org/), but the differences between the most important UNIX kernels don't justify the problems they make.

Oh, we're completely cross-platform these days! That means it runs on both RHEL and Ubuntu.

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Perhaps you missed the sarcasm?

ha ha ha

ha ha only serious http://www.catb.org/jargon/html/H/ha-ha-only-serious.html

It's VAXocentrism for the 21st century. http://www.catb.org/jargon/html/V/vaxocentrism.html

Interesting to think that the assumptions of C as a language evolved mostly against the VAX architecture. It seems that if the VAX doesn't make a distinction, then C doesn't (tend to) have any concept of that distinction either. Examples:

- Pointer types are basically fungible in C (otherwise there would be no void-ptr type)

- There's no compile-time knowledge of the segment a pointer references to prevent you from dereferencing a pointer to an offset from segment A when segment B is loaded (compare this to Rust's parameterization of Box types by their allocator)

- Struct padding is painful and tacked on

- "unsigned char" isn't default even though it'd make much more sense for it to be (What "char"acter is negative? You can have a signed byte/octet, but a character is—in 1979, at least—basically an enum/sum type.

Actually C disallows converting function pointers to/from void pointers.

Can you get away with that in pre-ANSI C? I wouldn't be surprised.

for pre-ANSI C most of these questions are answered by "it depends on the compiler" which is why ANSI C happened. Of course the answer is still "it depends on the compiler" for this behavior, since it's not defined what it does in ANSI C, just that it's not portable to do it.

I remember working on a Fujitsu box in 1993, which used some sort of weird System V Unix with pre-ANSI C and weirdly abbreviated man pages in Engrish. (shudder) Yeah.

Against the PDP-11, which the VAX directly descended from, but yes. Unix and C were written for the PDP series.

Oh this is definitely true. Most unix programs are not portable to POSIX, even when they don't intentionally use features that aren't in POSIX (e.g. kqueue).

UNIX API fragmentation is still a problem, but my point is that POSIX was trying to unify existing implementations rather than a greenfields project to generate a set of portable APIs.

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