Re: configure fails on checking ino_t

[Eric Blake <eblake@redhat.com>]

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On 06/07/2017 05:11 PM, Lloyd Wood via cygwin wrote:

Please don't top-post on technical lists.

> Aha! just slightly later in config.log:
> 
> configure:17957: checking for ino_t 
> configure:17957: gcc -c -g -O2  conftest.c >&5 
> configure:17957: $? = 0 
> configure:17957: gcc -c -g -O2  conftest.c >&5 
> conftest.c: In function 'main': 
> conftest.c:94:20: error: expected expression before ')' token 
> if (sizeof ((ino_t))) 
> ^ 

This _particular_ failure is expected (you aren't showing enough of the
config.log output).  Remember, to determine if something is a type vs.
an expression, autoconf performs TWO compilation tests, and relies on
the fact that sizeof(expr) and sizeof((expr)) both compile, but
sizeof(type) compiles while sizeof((type)) must fail.  The back-to-back
compilation is necessary to ensure that something being probed for is a
type name rather than an arbitray expression.

So just because _some_ tests fail (as expected) does not mean that this
particular failure is where configure is messing up.


-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org


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