Re: [dpdk-dev] [PATCH v2 4/4] Link apps/DSOs against EXECENV_LDLIBS with --as-needed

[Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>]

On Wed, Oct 08, 2014 at 05:38:52PM +0200, Thomas Monjalon wrote:
> Please could you explain why patch is needed?
> 
Hi Thomas,

Basically this patch just adds missing dependencies to DPDK DSOs. so the 
DL knows about them.

As an example, if we were to build an application against DPDK without
adding the libs defined in EXECENV_LDLIBS:

-- pre-patch:
LD test
test_red.o: In function `ovfl_test1':
test_red.c:(.text+0x1ac6): undefined reference to `log'
test_red.c:(.text+0x1ad3): undefined reference to `ceil'
test_red.o: In function `perf2_test':
test_red.c:(.text+0x2314): undefined reference to `pow'
test_red.o: In function `func_test3':
test_red.c:(.text+0x28d7): undefined reference to `pow'
test_red.o: In function `func_test6':
test_red.c:(.text+0x324c): undefined reference to `pow'
dpdk/x86_64-native-linuxapp-gcc/lib/libintel_dpdk.so: undefined reference to `dlopen'
dpdk/x86_64-native-linuxapp-gcc/lib/libintel_dpdk.so: undefined reference to `log2'
dpdk/x86_64-native-linuxapp-gcc/lib/libintel_dpdk.so: undefined reference to `dlerror'
dpdk/x86_64-native-linuxapp-gcc/lib/libintel_dpdk.so: undefined reference to `round'

-- post-patch:
LD test
/usr/bin/ld: test_red.o: undefined reference to symbol 'log@@GLIBC_2.2.5'
/usr/bin/ld: note: 'log@@GLIBC_2.2.5' is defined in DSO /lib64/libm.so.6 so try adding it to the linker command line
/lib64/libm.so.6: could not read symbols: Invalid operation

Thanks,
Sergio

> -- 
> Thomas