[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [PATCH v2] Do not use %m in common code to print error messages
From: |
Thomas Huth |
Subject: |
Re: [PATCH v2] Do not use %m in common code to print error messages |
Date: |
Fri, 18 Oct 2019 18:01:22 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 |
On 18/10/2019 15.49, Kamil Rytarowski wrote:
> On 18.10.2019 15:42, Stefano Garzarella wrote:
>> On Fri, Oct 18, 2019 at 03:07:16PM +0200, Thomas Huth wrote:
>>> The %m format specifier is an extension from glibc - and when compiling
>>> QEMU for NetBSD, the compiler correctly complains, e.g.:
>>>
>>> /home/qemu/qemu-test.ELjfrQ/src/util/main-loop.c: In function
>>> 'sigfd_handler':
>>> /home/qemu/qemu-test.ELjfrQ/src/util/main-loop.c:64:13: warning: %m is only
>>> allowed in syslog(3) like functions [-Wformat=]
>>> printf("read from sigfd returned %zd: %m\n", len);
>>> ^
>>> Let's use g_strerror() here instead, which is an easy-to-use wrapper
>>> around the thread-safe strerror_r() function.
>>>
>>> While we're at it, also convert the "printf()" in main-loop.c into
>>> the preferred "error_report()".
>>>
>>> Signed-off-by: Thomas Huth <address@hidden>
>>> ---
>>> v2: Do not try to g_free() the strings
>>>
>>> hw/misc/tmp421.c | 4 ++--
>>> util/main-loop.c | 3 ++-
>>> util/systemd.c | 4 ++--
>>> 3 files changed, 6 insertions(+), 5 deletions(-)
>>
>> There are many uses of %m also in hw/vfio/ but that's Linux stuff.
>> Should we change those too or it doesn't matter since it never really
>> compiled on NetBSD?
>
> It's a gnu (glibc) extension and linux can use alternative libc
> implementations. Probably most of them capable to host qemu use %m.
I think I read somewhere that other libcs on Linux also support %m (like
musl), but I just can't find that reference anymore. Anyway, we can
still fix that later in case someone hits the issue.
>> Anyway, this patch LGTM:
>> Reviewed-by: Stefano Garzarella <address@hidden>
Thanks,
Thomas