CodingGuidelines: st_mtimespec vs st_mtim vs st_mtime

Most unfortunately macOS does not support st_[amc]tim for timestamps down to nanosecond resolution as POSIX systems. Signed-off-by: Junio C Hamano <gitster@pobox.com>

Junio C Hamano committed Apr 10, 2026 at 11:10 UTC b96490241e342fe1aecbd3c4f40de6998d2a3eaa
1 file changed +6
Documentation/CodingGuidelines
+6
@@ -681,6 +681,12 @@ For C programs:
681 char *dogs[] = ...;
682 walk_all_dogs(dogs);
683
684 + - For file timestamps, do not use "st_mtim" (and other timestamp
685 + members in "struct stat") unconditionally; not everybody is POSIX
686 + (grep for USE_ST_TIMESPEC). If you only need a timestamp in whole
687 + second resolution, "st_mtime" should work fine everywhere.
688 +
689 +
690 For Perl programs:
691
692 - Most of the C guidelines above apply.