Warnings in headers when building libpcap with dpdk and clang

Warnings in headers when building libpcap with dpdk and clang

[Francois]

Hello,

I notice many warnings. To reproduce:

On Debian bookworm.

sudo apt install dpdk-dev

git clone https://git.tcpdump.org/libpcap

# build with clang

$ ./autogen.sh

$ ./configure CC=clang-16 --with-dpdk

$ make

Warning lines:
/usr/include/dpdk/rte_ring_elem_pvt.h:13:36: warning: 'GCC_VERSION' is not defined, evaluates to 0 [-Wundef]
/usr/include/dpdk/rte_ring_generic_pvt.h:93:28: warning: possible misuse of comma operator here [-Wcomma]
/usr/include/dpdk/rte_ring_elem_pvt.h:391:36: warning: 'GCC_VERSION' is not defined, evaluates to 0 [-Wundef]
/usr/include/dpdk/../x86_64-linux-gnu/dpdk/rte_memcpy.h:25:36: warning: 'GCC_VERSION' is not defined, evaluates to 0 [-Wundef]
/usr/include/dpdk/../x86_64-linux-gnu/dpdk/rte_memcpy.h:873:36: warning: 'GCC_VERSION' is not defined, evaluates to 0 [-Wundef]
/usr/include/dpdk/rte_flow.h:176:6: warning: declaration is marked with '@deprecated' command but does not have a deprecation attribute [-Wdocumentation-deprecated-sync]
/usr/include/dpdk/rte_flow.h:674:5: warning: declaration is marked with '@deprecated' command but does not have a deprecation attribute [-Wdocumentation-deprecated-sync]
/usr/include/dpdk/rte_flow.h:2223:6: warning: declaration is marked with '@deprecated' command but does not have a deprecation attribute [-Wdocumentation-deprecated-sync]
/usr/include/dpdk/rte_flow.h:2235:6: warning: declaration is marked with '@deprecated' command but does not have a deprecation attribute [-Wdocumentation-deprecated-sync]
/usr/include/dpdk/rte_flow.h:2247:6: warning: declaration is marked with '@deprecated' command but does not have a deprecation attribute [-Wdocumentation-deprecated-sync]
/usr/include/dpdk/rte_flow.h:2656:6: warning: declaration is marked with '@deprecated' command but does not have a deprecation attribute [-Wdocumentation-deprecated-sync]
/usr/include/dpdk/rte_flow.h:2940:5: warning: declaration is marked with '@deprecated' command but does not have a deprecation attribute [-Wdocumentation-deprecated-sync]
/usr/include/dpdk/rte_flow.h:2962:5: warning: declaration is marked with '@deprecated' command but does not have a deprecation attribute [-Wdocumentation-deprecated-sync]
/usr/include/dpdk/rte_flow.h:4218:5: warning: declaration is marked with '@deprecated' command but does not have a deprecation attribute [-Wdocumentation-deprecated-sync]
/usr/include/dpdk/rte_ethdev.h:3568:10: warning: unrecognized parameter passing direction, valid directions are '[in]', '[out]' and '[in,out]' [-Wdocumentation]
/usr/include/dpdk/rte_ethdev.h:5375:10: warning: unrecognized parameter passing direction, valid directions are '[in]', '[out]' and '[in,out]' [-Wdocumentation]

What do you think?

-- 
Francois

RE: Warnings in headers when building libpcap with dpdk and clang

[Marat Khalili]

> -----Original Message-----
> From: Francois <devel.fx.lebail@orange.fr>
> Sent: Thursday 14 August 2025 13:54
> To: dev@dpdk.org
> Subject: Warnings in headers when building libpcap with dpdk and clang
> 
> Hello,
> 
> I notice many warnings. To reproduce:
> 
> On Debian bookworm.
> 
> sudo apt install dpdk-dev
> 
> git clone https://git.tcpdump.org/libpcap
> 
> # build with clang
> 
> $ ./autogen.sh
> 
> $ ./configure CC=clang-16 --with-dpdk
> 
> $ make
> 
> Warning lines:
> /usr/include/dpdk/rte_ring_elem_pvt.h:13:36: warning: 'GCC_VERSION' is not defined, evaluates to 0 [-
> Wundef]

> What do you think?

For the first warning there was a commit 3cb34fb0b0 "build: set toolchain macros from predefined macros" dated 2024-01-02 that was fixing similar issue. It is possible that documentation issues were fixed since bookworm-shipped version 22.11 as well. Depending on your goals you may try newer DPDK version, compiling libpcap with gcc and/or fewer warnings or just ignoring these warnings.