cygwin fork()

Dave Korn
Fri Sep 1 17:57:00 GMT 2006

On 01 September 2006 18:47, clayne@anodized.HIPPO wrote:

> I found the real culprit, which I had also ifdef'd out because it looked
> bogus and crufty:
> /* Return 1 if a seek on FD will succeed. */
> #ifndef __CYGWIN__
> #  define fd_is_seekable(fd) (lseek ((fd), 0L, SEEK_CUR) >= 0)
> #else
> #  define fd_is_seekable(fd) 0
> #endif /* __CYGWIN__ */

  Yeeesh.  This is a terrible way of dealing with the fact that you can't seek
a stream accurately if you open it in text mode, because of the ambiguity
about whether you've advanced one or two chars through the underlying file
when you see an LF that could perhaps have actually been a CR/LF.  What we
really want is 

#define fd_is_seekable(fd)  fd_is_in_binary_not_text_mode(fd)

...although of course I'm paraphrasing there.

  Anyway, congratulations, well tracked down!  Definitely one to raise with

Can't think of a witty .sigline today....

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