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Subject: Re: architecture dependent directory of C header
From: Xi Ruoyao <xry111@mengyan1223.wang>
To: Da Shi Cao <dscao999@hotmail.com>, "gcc-help@gcc.gnu.org"
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Date: Mon, 28 Mar 2022 18:29:06 +0800
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On Sun, 2022-03-27 at 15:14 +0000, Da Shi Cao wrote:
> Hi Ruoyao,
>=20
> I'm trying to build a cross gcc on X86_64, with target armhf. The
> cross gcc will have /usr/include/arm-linux-gnueabihf, which is already
> populated, as its header search directory if the gcc is configured
> with:
> --enable-multiarch --with-arch=3Darmv7-a --with-fpu=3Dneon-vfpv4 --with-
> float=3Dhard
>=20
> But to build a gcc with target aarch64, only --with-arch=3Darmv8-a is
> used in the configuration and /usr/include/aarch64-linux-gnueabi will
> be among the header search directories of the resulting gcc. I'll do
> this build again to confirm it.
>=20
Yes this is the expected behavior.

Note that the "multiarch" directory is normally not used for a cross
compiler.  If your cross compiler relies on something in /usr/include,
it looks like you are doing something wrong.  Generally a sysroot is
used by a cross compiler to find target headers and libraries.
--=20
Xi Ruoyao <xry111@mengyan1223.wang>
School of Aerospace Science and Technology, Xidian University