patch 8.2.3510: changes are only detected with one second accuracyv8.2.3510

Problem:    Changes are only detected with one second accuracy.
Solution:   Use the nanosecond time if possible.  (Leah Neukirchen,
            closes #8873, closes #8875)

1 files changed, 25 insertions, 0 deletions

diff --git a/src/configure.ac b/src/configure.ac
index bb77485f31..3316f48242 100644
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -3843,6 +3843,31 @@ main() {struct stat st;  exit(stat("configure/", &st) != 0); }
 if test "x$vim_cv_stat_ignores_slash" = "xyes" ; then
   AC_DEFINE(STAT_IGNORES_SLASH)
 fi
+
+dnl nanoseconds field of struct stat
+AC_CACHE_CHECK([for nanoseconds field of struct stat],
+  ac_cv_struct_st_mtim_nsec,
+  [ac_save_CPPFLAGS="$CPPFLAGS"
+   ac_cv_struct_st_mtim_nsec=no
+   # st_mtim.tv_nsec -- the usual case
+   # st_mtim._tv_nsec -- Solaris 2.6, if
+   #	(defined _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED == 1
+   #	 && !defined __EXTENSIONS__)
+   # st_mtim.st__tim.tv_nsec -- UnixWare 2.1.2
+   # st_mtime_n -- AIX 5.2 and above
+   # st_mtimespec.tv_nsec -- Darwin (Mac OSX)
+   for ac_val in st_mtim.tv_nsec st_mtim._tv_nsec st_mtim.st__tim.tv_nsec st_mtime_n st_mtimespec.tv_nsec; do
+     CPPFLAGS="$ac_save_CPPFLAGS -DST_MTIM_NSEC=$ac_val"
+     AC_TRY_COMPILE([#include <sys/types.h>
+#include <sys/stat.h>], [struct stat s; s.ST_MTIM_NSEC;],
+       [ac_cv_struct_st_mtim_nsec=$ac_val; break])
+   done
+   CPPFLAGS="$ac_save_CPPFLAGS"
+])
+if test $ac_cv_struct_st_mtim_nsec != no; then
+  AC_DEFINE_UNQUOTED([ST_MTIM_NSEC], [$ac_cv_struct_st_mtim_nsec],
+  [Define if struct stat contains a nanoseconds field])
+fi
   
 dnl Link with iconv for charset translation, if not found without library.
 dnl check for iconv() requires including iconv.h