Re: [PATCH v1 1/1] selftests: net: af_unix: cast void* to char* in call to macro TH_LOG()

[Simon Horman <horms@kernel.org>]

On Mon, Aug 12, 2024 at 02:22:58AM +0200, Mirsad Todorovac wrote:
> GCC 13.2.0 reported warning about (void *) beeing used as a param where (char *) is expected:

nit: being

> 
> In file included from msg_oob.c:14:
> msg_oob.c: In function ‘__recvpair’:
> ../../kselftest_harness.h:106:40: warning: format ‘%s’ expects argument of type ‘char *’,
> 							but argument 6 has type ‘const void *’ [-Wformat=]
>   106 |                 fprintf(TH_LOG_STREAM, "# %s:%d:%s:" fmt "\n", \
>       |                                        ^~~~~~~~~~~~~
> ../../kselftest_harness.h:101:17: note: in expansion of macro ‘__TH_LOG’
>   101 |                 __TH_LOG(fmt, ##__VA_ARGS__); \
>       |                 ^~~~~~~~
> msg_oob.c:235:17: note: in expansion of macro ‘TH_LOG’
>   235 |                 TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : expected_buf);
>       |                 ^~~~~~
> ../../kselftest_harness.h:106:40: warning: format ‘%s’ expects argument of type ‘char *’,
> 							but argument 6 has type ‘const void *’ [-Wformat=]
>   106 |                 fprintf(TH_LOG_STREAM, "# %s:%d:%s:" fmt "\n", \
>       |                                        ^~~~~~~~~~~~~
> ../../kselftest_harness.h:101:17: note: in expansion of macro ‘__TH_LOG’
>   101 |                 __TH_LOG(fmt, ##__VA_ARGS__); \
>       |                 ^~~~~~~~
> msg_oob.c:259:25: note: in expansion of macro ‘TH_LOG’
>   259 |                 TH_LOG("Expected:%s", expected_errno ? strerror(expected_errno) : expected_buf);
>       |                 ^~~~~~

Thanks, I see this too.

> Casting param to (char *) silences the warning.

It seems that all callers pass a string as the expected_errno argument.
Perhaps it's type could be updated to char *, if that is what it is.
I think this would avoid the need to cast.

> Fixes: d098d77232c37 ("selftest: af_unix: Add msg_oob.c.")
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: Shuah Khan <shuah@kernel.org>
> Cc: Kuniyuki Iwashima <kuniyu@amazon.com>
> Cc: netdev@vger.kernel.org
> Cc: linux-kselftest@vger.kernel.org
> Signed-off-by: Mirsad Todorovac <mtodorovac69@gmail.com>

...