[dpdk-dev] Useful: Simple C++ program & Makefile

[Dan Kan]

I forgot to add that you will also need to add -D__STDC_LIMIT_MACROS
because C99 standard specifies that limits such as INT8_MAX should only be
defined if explicitly requested. Also with g++, you can no longer use
non-trivial designated initializers which are used extensively throughout
dpdk sample apps. For example,

static const struct rte_eth_rxconf rx_conf = {
    .rx_thresh = {
        .pthresh = RX_PTHRESH,
        .hthresh = RX_HTHRESH,
        .wthresh = RX_WTHRESH,
    },
    .rx_free_thresh = 32,
};


Basically, use gcc to build the dpdk libraries. Then, use g++ to build your
own code and link against the built libraries.

Dan


On Fri, Jan 10, 2014 at 12:19 PM, Dan Kan <dan at nyansa.com> wrote:

> Hamid,
> I'm in the same situation as you in which I would like to write most of
> the application logic in C++. I was able to use CC=g++ by slightly
> modifying the makefiles in mk. I replaced all occurrences of "%.c" with
> "%.cc" using the following command.
>
> find . -name "*.mk" -exec sed -i 's/%\.c\([^[:alpha:]]\)/%\.cc\1/g' {} \;
>
> I also remove some warning flags as errors.
>
> Here are the diffs:
>
> diff -r mk/internal/rte.compile-pre.mk ../temp/dpdk-1.5.1r2/mk/internal/
> rte.compile-pre.mk
> 39c39
> < src2obj = $(strip $(patsubst %.cc,%.o,\
> ---
> > src2obj = $(strip $(patsubst %.c,%.o,\
> 48c48
> < src2dep = $(strip $(call dotfile,$(patsubst %.cc,%.o.d, \
> ---
> > src2dep = $(strip $(call dotfile,$(patsubst %.c,%.o.d, \
> 53c53
> < src2cmd = $(strip $(call dotfile,$(patsubst %.cc,%.o.cmd, \
> ---
> > src2cmd = $(strip $(call dotfile,$(patsubst %.c,%.o.cmd, \
> 125c125
> < %.o: %.cc $$(wildcard $$(dep_$$@)) $$(DEP_$$(@)) FORCE
> ---
> > %.o: %.c $$(wildcard $$(dep_$$@)) $$(DEP_$$(@)) FORCE
> diff -r mk/rte.module.mk ../temp/dpdk-1.5.1r2/mk/rte.module.mk
> 36,37c36,37
> < ifneq ($(MODULE),$(notdir $(SRCS-y:%.cc=%)))
> < $(MODULE)-objs += $(notdir $(SRCS-y:%.cc=%.o))
> ---
> > ifneq ($(MODULE),$(notdir $(SRCS-y:%.c=%)))
> > $(MODULE)-objs += $(notdir $(SRCS-y:%.c=%.o))
> diff -r mk/toolchain/gcc/rte.vars.mk../temp/dpdk-1.5.1r2/mk/toolchain/gcc/
> rte.vars.mk
> 71,73c71,73
> < WERROR_FLAGS := -W -Wall -Werror
> < WERROR_FLAGS += -Wmissing-declarations -Wpointer-arith
> < WERROR_FLAGS += -Wcast-align -Wcast-qual
> ---
> > WERROR_FLAGS := -W -Wall -Werror -Wstrict-prototypes -Wmissing-prototypes
> > WERROR_FLAGS += -Wmissing-declarations -Wold-style-definition
> -Wpointer-arith
> > WERROR_FLAGS += -Wcast-align -Wnested-externs -Wcast-qual
>
>
> Dan
>
>
> On Thu, Jan 9, 2014 at 10:30 PM, Hamid Ramazani <mrramazani at gmail.com>wrote:
>
>> > I don't exactly know what is needed for C++. Please keep us informed.
>>
>> Hey Thomas,
>>
>> I've attached a simple program (main.cpp main.h and Makefile) that has
>> a C++ class and just prints some messages in the output.
>> Despite the fact that it's working fine, I'm sure the Makefile could
>> be written much better; Maybe I made it completer in future.
>>
>> All the Best,
>> --Hamid
>>
>> On 1/3/14, Thomas Monjalon <thomas.monjalon at 6wind.com> wrote:
>> > Hello,
>> >
>> > 03/01/2014 11:48, Hamid Ramazani :
>> >> eal_timer.c:(.text+0x42c): undefined reference to `clock_gettime'
>> >
>> > From "man clock_gettime":
>> > Link with -lrt (only for glibc versions before 2.17).
>> >
>> >>      g++ -m64 -pthread  -march=native -DRTE_MACHINE_CPUFLAG_SSE
>> >> -DRTE_MACHINE_CPUFLAG_SSE2 -DRTE_MACHINE_CPUFLAG_SSSE3
>> >>
>> -DRTE_COMPILE_TIME_CPUFLAGS=RTE_CPUFLAG_SSE,RTE_CPUFLAG_SSE2,RTE_CPUFLAG_SS
>> >> SE3 -I/home/hamid/dpdk/dpdk-1.5.1r1/examples/sample/build/include
>> >> -I/home/hamid/dpdk/dpdk-1.5.1r1/x86_64-default-linuxapp-gcc/include
>> >> -include
>> >>
>> /home/hamid/dpdk/dpdk-1.5.1r1/x86_64-default-linuxapp-gcc/include/rte_conf
>> >> ig.h -O3 -W -Wall -Werror -Wmissing-declarations -Wpointer-arith
>> >> -Wcast-align -Wcast-qual -Wformat-nonliteral -Wformat-security -Wundef
>> >> -Wwrite-strings -Wl,-melf_x86_64 -Wl,-export-dynamic sample.cpp -o
>> >> sample -Wl,-L/home/hamid/dpdk/dpdk-1.5.1r1/examples/sample/build/lib
>> >> -Wl,-L/home/hamid/dpdk/dpdk-1.5.1r1/x86_64-default-linuxapp-gcc/lib
>> >> -Wl,-L/home/hamid/dpdk/dpdk-1.5.1r1/x86_64-default-linuxapp-gcc/lib
>> >> -Wl,-lrte_kni -Wl,-lrte_pmd_e1000 -Wl,-lrte_pmd_ixgbe -Wl,-lrte_mbuf
>> >> -Wl,-lrte_cmdline -Wl,-lrte_timer -Wl,-lrte_hash -Wl,-lrte_lpm
>> >> -Wl,--start-group -Wl,-lethdev -Wl,-lrte_malloc -Wl,-lrte_mempool
>> >> -Wl,-lrte_ring -Wl,-lrte_eal -Wl,-ldl -Wl,--end-group
>> >
>> > Try CONFIG_RTE_BUILD_COMBINE_LIBS=y and -lintel_dpdk instead of all
>> these
>> > libraries. You can also remove the warning options if you want.
>> >
>> > You can also try to build your Makefile by including files like
>> > mk/rte.extapp.mk and defining CC=g++.
>> > I don't exactly know what is needed for C++. Please keep us informed.
>> >
>> > --
>> > Thomas
>> >
>>
>
>