[dpdk-dev] warnings when including DPDK headers from a C++17 source file

[dpdk-dev] warnings when including DPDK headers from a C++17 source file

[Montorsi, Francesco]

Hi all,


I just noticed that, because of the removal of the "register" keyword in C++17, when I compile my DPDK-enabled code with -std=c++17 I get the following:



In file included from ../../../Third-Party/cpp-libs/dpdk/include/rte_ether.h:53:0,
                 from ../../../Third-Party/cpp-libs/dpdk/include/rte_ethdev.h:186,
                 from HwEmulCaptureDPDK.cpp:43:
../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder.h: In function 'uint16_t rte_arch_bswap16(uint16_t)':
../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder.h:57:20: warning: ISO C++1z does not allow 'register' storage class specifier [-Wregister]
  register uint16_t x = _x;
                    ^
../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder.h: In function 'uint32_t rte_arch_bswap32(uint32_t)':
../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder.h:72:20: warning: ISO C++1z does not allow 'register' storage class specifier [-Wregister]
  register uint32_t x = _x;
                    ^
In file included from ../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder.h:121:0,
                 from ../../../Third-Party/cpp-libs/dpdk/include/rte_ether.h:53,
                 from ../../../Third-Party/cpp-libs/dpdk/include/rte_ethdev.h:186,
                 from HwEmulCaptureDPDK.cpp:43:
../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder_64.h: In function 'uint64_t rte_arch_bswap64(uint64_t)':
../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder_64.h:52:20: warning: ISO C++1z does not allow 'register' storage class specifier [-Wregister]
  register uint64_t x = _x;
                    ^


?Just thought to let you know... that's a small issue for me since I'm using -Werror


Thanks,
Francesco

Re: [dpdk-dev] warnings when including DPDK headers from a C++17 source file

[Stephen Hemminger]

On Fri, 13 Jul 2018 13:51:21 +0000
"Montorsi, Francesco" <fmontorsi@empirix.com> wrote:

> Hi all,
> 
> 
> I just noticed that, because of the removal of the "register" keyword in C++17, when I compile my DPDK-enabled code with -std=c++17 I get the following:
> 
> 
> 
> In file included from ../../../Third-Party/cpp-libs/dpdk/include/rte_ether.h:53:0,
>                  from ../../../Third-Party/cpp-libs/dpdk/include/rte_ethdev.h:186,
>                  from HwEmulCaptureDPDK.cpp:43:
> ../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder.h: In function 'uint16_t rte_arch_bswap16(uint16_t)':
> ../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder.h:57:20: warning: ISO C++1z does not allow 'register' storage class specifier [-Wregister]
>   register uint16_t x = _x;
>                     ^
> ../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder.h: In function 'uint32_t rte_arch_bswap32(uint32_t)':
> ../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder.h:72:20: warning: ISO C++1z does not allow 'register' storage class specifier [-Wregister]
>   register uint32_t x = _x;
>                     ^
> In file included from ../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder.h:121:0,
>                  from ../../../Third-Party/cpp-libs/dpdk/include/rte_ether.h:53,
>                  from ../../../Third-Party/cpp-libs/dpdk/include/rte_ethdev.h:186,
>                  from HwEmulCaptureDPDK.cpp:43:
> ../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder_64.h: In function 'uint64_t rte_arch_bswap64(uint64_t)':
> ../../../Third-Party/cpp-libs/dpdk/include/rte_byteorder_64.h:52:20: warning: ISO C++1z does not allow 'register' storage class specifier [-Wregister]
>   register uint64_t x = _x;
>                     ^
> 
> 
> ?Just thought to let you know... that's a small issue for me since I'm using -Werror
> 
> 
> Thanks,
> Francesco
> 
> 

Why is DPDK code using register keyword at all? It is ignored by modern compilers.

Re: [dpdk-dev] warnings when including DPDK headers from a C++17 source file

[Montorsi, Francesco]

Hi,

________________________________________
From: Stephen Hemminger <stephen@networkplumber.org>
Sent: Friday, July 13, 2018 5:52 PM
To: Montorsi, Francesco
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] warnings when including DPDK headers from a C++17 source file

> Why is DPDK code using register keyword at all? It is ignored by modern compilers.

that's my question as well :)

Maybe register keyword could be removed at least from header files to make the life easier to whoever is using C++17... right now I worked around that by placing -Werror -Wno-register, but that's perhaps not the best solution

Francesco