stat: support high resolution time stamps.

* configure (have_sys_stat): New variable. Set to y when our
test detects <sys/stat.h>. New test added for the presence of
high resolution time stamps in struct stat. If we have these,
we #define HAVE_STAT_NSEC 1 in config.h.

* share/txr/stdlib/path-test.tl (path-newer): Compare
nanosecond parts of the modification time if the seconds are
equal, improving the resolution of the test.

* sysif.c (atime_nsec_s, mtime_nsec_s, ctime_nsec_s): New
symbol variables.
(stat_to_struct): If nanosecond resolution is available, set
the new nanosecond slots from the three tv_nsec fields in
struct stat. Otherwise, set the new slots to zero.
(sysif_init): Initialize the new symbol variables. Add the
three new slots to the stat struct.

* sysif.c (atime_nsec_s, mtime_nsec_s, ctime_nsec_s):
Declared.

* txr.1: Documented new atime-nsec, mtime-nsec and ctime-nsec
slots of stat structure. Added note to path-newer mentioning
high resolution support.

1 files changed, 3 insertions, 1 deletions

diff --git a/sysif.h b/sysif.h
index 15625b24..cc817402 100644
--- a/sysif.h
+++ b/sysif.h
@@ -31,7 +31,9 @@ extern val gid_k, rdev_k, size_k, blksize_k, blocks_k;
 extern val atime_k, mtime_k, ctime_k;
 extern val dev_s, ino_s, mode_s, nlink_s, uid_s;
 extern val gid_s, rdev_s, size_s, blksize_s, blocks_s;
-extern val atime_s, mtime_s, ctime_s, path_s;
+extern val atime_s, mtime_s, ctime_s;
+extern val atime_nsec_s, mtime_nsec_s, ctime_nsec_s;
+extern val path_s;
 
 #if !HAVE_FTRUNCATE
 typedef long off_t;