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RE: libcurl on QNX 6

From: <>
Date: Tue, 8 Jan 2002 15:54:28 -0000


I checked out the new QNX entry in docs/INSTALL on your WWW and wondered if
it could be worded better as that wasn't what I actually did in the end, as
there are various socket() calls in libcurl which could all potentially
return >FD_SETSIZE.

I would suggest the following words:

"As QNX is targetted for resource constrained environments, the QNX headers
set conservative limits. This includes the FD_SETSIZE macro, set by default
to 32. Socket descriptors returned within the CURL library may exceed this,
resulting in memory faults/SIGSEGV crashes when passed into select(..) calls
using fd_set macros.

A good all-round solution to this is to override the default when building
libcurl, by overriding CFLAGS during configure, example
# configure CFLAGS='-DFD_SETSIZE=64 -g -O2'"

Hope it makes sense...

> -----Original Message-----
> From: Daniel Stenberg []
> Sent: Monday 07 January 2002 03:19 PM
> To: Bentham, David (Poole)
> Cc: libcurl Mailing list
> Subject: RE: libcurl on QNX 6
> On Thu, 3 Jan 2002 wrote:
> > Fortunately in the QNX headers its defined as
> >
> > #ifndef FD_SETSIZE
> > #define FD_SETSIZE 32
> > #endif
> >
> > so its relatively easy to override without changing the original
> > definition. QNX claim posix compliance so this definition style could be
> > standard in other o/s's. Eg Microsoft Visual C++ 6 defines it similarly,
> > but its set to 64.
> The standard Linux headers seems to set the same define to 1024!
> > My initial thoughts are to put some simple test in the Makefile?
> With
> > a 'configure' option to pass in a user- (or best-guess) override
> definition
> > in the GCC options.
> That might be a good idea. The annoying part will probably be that the
> define
> won't be available in any known header, so we'll have to search a wide
> range
> of headers. And when we find out, we can't be sure we just change it like
> that, without affecting other things.
> Or can we?
> Anyway, I added your previous notes to the docs/INSTALL document in a
> "QNX"
> section, so that it won't be forgotten in the future.
> > On the other hand, it seems bizzarre that the o/s function call to
> > socket(..) returns a socket descriptor outside its own arbitrary
> range...
> > perhaps I'll inform QNX about this.
> I find it odd too.
> Thanks anyway for your digging and informations!
> --
> Daniel Stenberg -- curl groks URLs --
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Received on 2002-01-08