[Buildroot] Problem compiling c++ files

hartleys hartleys at visionengravers.com
Thu Aug 14 01:29:30 UTC 2008

On Wednesday, August 13, 2008 5:49 PM, hartleys wrote:
> Hello all,
> I'm not sure if this is a buildroot problem or something with
> automake. Hopefully someone can help.
> I'm trying to cross-compile a c++ program under buildroot with
> an external toolchain. For some reason the ./configure output
> does not set the CXX and CXXCPP variables with the full path to
> the executables. Then during the make step I get the following
> error:


I think I found the problem but I'm not sure where to fix it...

Toward the end of package/Makefile.in there is this setting:

ifneq ($(BR2_GCC_CROSS_CXX),y)

I think that's what's mucking up automake. As far as I can tell
BR2_GCC_CROSS_CXX is only set in toolchain/gcc/Config.in. Walking thru
the various configs I get.

1) I'm using an external binary toolchain (BR2_TOOLCHAIN_EXTERNAL=y from
   This results in BR2_TOOLCHAIN_SOURCE=n (same file).
2) When toolchain/Config.in.2 then gets processed the whole file gets
skipped except for the source "toolchain/kernel-headers/Config.in" at
the beginning.
   This results in toolchain/gcc/Config.in getting skipped.

If I add the following to toolchain/external-toolchain/Config.in the
build works fine.

	bool "C++ cross-compiler support"
	  Enable C++ cross-compiler support.

I'm just not sure if this is the correct approach.


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