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@xxxxxxxxxx>
---
src/meta.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/src/meta.c b/src/meta.c
index bf2201009a8c..8508b11e70ce 100644
--- a/src/meta.c
+++ b/src/meta.c
@@ -10,6 +10,8 @@
* Development of this code funded by Astaro AG (http://www.astaro.com/)
*/
+#define _GNU_SOURCE
+
#include <errno.h>
#include <limits.h>
#include <stddef.h>
@@ -25,6 +27,7 @@
#include <linux/netfilter.h>
#include <linux/pkt_sched.h>
#include <linux/if_packet.h>
+#include <time.h>
#include <nftables.h>
#include <expression.h>
@@ -37,10 +40,6 @@
#include <iface.h>
#include <json.h>
-#define _XOPEN_SOURCE
-#define __USE_XOPEN
-#include <time.h>
-
static void tchandle_type_print(const struct expr *expr,
struct output_ctx *octx)
{
--
2.41.0
