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From: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>
To: Thomas Monjalon <thomas.monjalon@6wind.com>
CC: "dev@dpdk.org" <dev@dpdk.org>
Thread-Topic: [dpdk-dev] [PATCH] eal: fix c++ compilation issue with
 rte_delay_us()
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Date: Wed, 5 Oct 2016 10:17:40 +0000
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Subject: Re: [dpdk-dev] [PATCH] eal: fix c++ compilation issue with
 rte_delay_us()
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Hi Thomas,

>=20
> 2016-10-03 18:27, Konstantin Ananyev:
> > When compiling with C++, it treats
> > void (*rte_delay_us)(unsigned int us);
> > as definition of the global variable.
> > So further linking with librte_eal fails.
> >
> > Fixes: b4d63fb62240 ("eal: customize delay function")
>=20
> Applied, thanks
>=20
> I don't understand why it was not failing with C compilation?

Don't know off hand.
Yes, I would expect gcc to fail with same symptoms too.
But by some reason it puts it makes it a 'common' symbol:

$ cat rttm1.c

#include <stdio.h>
#include <rte_eal.h>
#include <rte_cycles.h>

int main(int argc, char *argv[])
{
        int ret =3D rte_eal_init(argc, argv);
        rte_delay_us(1);
        printf("return code: %d\n", ret);
        return ret;
}

$ gcc -m64 -pthread -o rttm1 rttm1.o -ldl   -L/${RTE_SDK}/${RTE_TARGET}/lib=
 -Wl,-lrte_eal
$ nm rttm1.o | grep rte_delay_us
0000000000000008 C rte_delay_us

Konstantin