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You are wrong because you keep asserting that file descriptor #2 is not defined to be standard error. The only place that defines the interface that uses file d

You are wrong because you keep asserting that file descriptor #2 is not defined to be standard error. The only place that defines the interface that uses file descriptors is POSIX and it defines standard error to be file descriptor #2, end of story. The sources you cite say nothing of file descriptors; they are all references to the standard FILE* interface in C. Those are opaque pointers and have nothing to do with 0, 1, or 2. You may be confused because I abbreviated "standard error" as "stderr", yet I was never talking about the C standard global "FILE *stderr". That was sloppy of me.

djcapelis 12y ago
When you printf to stderr, nothing in that function call is dependent on POSIX semantics. It is dependent on the semantics of C, which requires a stream called stderr to: 1) exist 2) be open when the program starts POSIX implements this using file descriptors and specifies that stderr is 2. I said: "strictly speaking, stderr does not have to be 2" which is true. A system is welcome to implement file descriptors and make stderr's something other than 2. It will be a blatant violation of POSIX, but complying with POSIX is optional. Systems that don't just aren't POSIX systems. Complying with the C standard? Not really optional.
- __david__ 12y ago
  > When you printf to stderr, nothing in that function call is dependent on POSIX semantics. fprintf(), but yeah. That is exactly what I've been saying, too. > I said: "strictly speaking, stderr does not have to be 2" which is true. Ok, but that's just like saying, "strictly speaking it's a valid C to write a bunch of zeros to a file and call it a jpeg." It might be technically true (complying with the JPEG spec is optional for C programs, too), but it's in no way a reasonable thing to argue for.
  - djcapelis 12y ago
    If I was arguing that it was reasonable, I'd have said that. I merely stated C allows it. Which it does. As for the printf/fprintf flub, totally.
    - __david__ 12y ago
      > If I was arguing that it was reasonable, I'd have said that. I merely stated C allows it. Which it does. That's the thing. The C standard does not allow it. The C standard merely never mentions it, which is a different thing entirely. Hence my analogy to JPEGs (which the C standard never mentions either). And I meant the argument itself is unreasonable. It makes no sense! I could just as well argue that the TCP/IP RFCs allow fd 2 to be something other than standard error. Or the HTTP 2.0 spec. Or the Ecmascript spec. Arguing that something is allowed by a spec that never mentions it and has absolutely nothing to do with it is not an argument.

djcapelis 12y ago

When you printf to stderr, nothing in that function call is dependent on POSIX semantics. It is dependent on the semantics of C, which requires a stream called stderr to: 1) exist 2) be open when the program starts POSIX implements this using file descriptors and specifies that stderr is 2. I said: "strictly speaking, stderr does not have to be 2" which is true. A system is welcome to implement file descriptors and make stderr's something other than 2. It will be a blatant violation of POSIX, but complying with POSIX is optional. Systems that don't just aren't POSIX systems. Complying with the C standard? Not really optional.

__david__ 12y ago
> When you printf to stderr, nothing in that function call is dependent on POSIX semantics. fprintf(), but yeah. That is exactly what I've been saying, too. > I said: "strictly speaking, stderr does not have to be 2" which is true. Ok, but that's just like saying, "strictly speaking it's a valid C to write a bunch of zeros to a file and call it a jpeg." It might be technically true (complying with the JPEG spec is optional for C programs, too), but it's in no way a reasonable thing to argue for.
- djcapelis 12y ago
  If I was arguing that it was reasonable, I'd have said that. I merely stated C allows it. Which it does. As for the printf/fprintf flub, totally.
  - __david__ 12y ago
    > If I was arguing that it was reasonable, I'd have said that. I merely stated C allows it. Which it does. That's the thing. The C standard does not allow it. The C standard merely never mentions it, which is a different thing entirely. Hence my analogy to JPEGs (which the C standard never mentions either). And I meant the argument itself is unreasonable. It makes no sense! I could just as well argue that the TCP/IP RFCs allow fd 2 to be something other than standard error. Or the HTTP 2.0 spec. Or the Ecmascript spec. Arguing that something is allowed by a spec that never mentions it and has absolutely nothing to do with it is not an argument.