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author | Thomas Haller <thaller@redhat.com> | 2023-08-25 13:36:29 +0200 |
---|---|---|
committer | Pablo Neira Ayuso <pablo@netfilter.org> | 2023-08-25 14:59:19 +0200 |
commit | 19231d4c896571fea397d43568c4b3562969c7e2 (patch) | |
tree | 6fbe566df3c4cf196e9abbb12389d10a96653be3 /src/nftutils.c | |
parent | 957b356e3bc94ff5721402e96ccfe3e8753e5768 (diff) |
meta: define _GNU_SOURCE to get strptime() from <time.h>
To use `strptime()`, the documentation indicates
#define _XOPEN_SOURCE
#include <time.h>
However, previously this was done wrongly.
For example, when building with musl we got a warning:
CC meta.lo
meta.c:40: warning: "_XOPEN_SOURCE" redefined
40 | #define _XOPEN_SOURCE
|
In file included from /usr/include/errno.h:8,
from meta.c:13:
/usr/include/features.h:16: note: this is the location of the previous definition
16 | #define _XOPEN_SOURCE 700
|
Defining "__USE_XOPEN" is wrong. This is a glibc internal define not for
the user.
Note that if we just set _XOPEN_SOURCE (or _XOPEN_SOURCE=700), we won't
get other things like "struct tm.tm_gmtoff".
Instead, we already define _GNU_SOURCE at other places. Do that here
too, it will give us strptime() and all is good.
Also, those directives should be defined as first thing (or via "-D"
command line). See [1].
This is also important, because to use "time_t" in a header, we would
need to include <time.h>. That only works, if we get the feature test
macros right. That is, define the _?_SOURCE macro as first thing.
[1] https://www.gnu.org/software/libc/manual/html_node/Feature-Test-Macros.html
Signed-off-by: Thomas Haller <thaller@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'src/nftutils.c')
0 files changed, 0 insertions, 0 deletions