[Buildroot] [PATCH 1/1] package/zeromq: enable kernel-based feature flags

[Arnout Vandecappelle <arnout@mind.be>]

On 21/04/15 22:47, Thomas Petazzoni wrote:
> Dear Arnout Vandecappelle,
> 
> On Wed, 18 Mar 2015 23:27:55 +0100, Arnout Vandecappelle wrote:
> 
>>  It's been a while ago, of course, but I think one problem was that the symbols
>> are also defined by the toolchain, so they exist even if the kernel doesn't
>> support them.
> 
> If the flags exist in the toolchain, then it means that the toolchain
> is using a certain version of the kernel headers. Running with a kernel
> older than that will anyway not work.
> 
> I mean, there are zillions of configure script that tests if the
> toolchain has syscall foo() or bar() by simply doing a compile time
> test. They don't actually check if the user is stupid enough to run on
> a system that has a kernel older than the kernel headers + C library
> combination used in the toolchain.
> 
> Or am I missing something specific to those flags?

 They are not syscalls but flags which are defined in <netinet/tcp.h>, which (at
least for uClibc) is copied verbatim from libc to the sysroot. So AFAICS the
libc doesn't actually check if it is really available in the kernel. Possibly
the kernels that didn't support these flags already defined (and ignored) them.


 Regards,
 Arnout


-- 
Arnout Vandecappelle                          arnout at mind be
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