tree-wide: never use the off_t unless glibc makes us use it

off_t is a really weird type as it is usually 64bit these days (at least
in sane programs), but could theoretically be 32bit. We don't support
off_t as 32bit builds though, but still constantly deal with safely
converting from off_t to other types and back for no point.

Hence, never use the type anymore. Always use uint64_t instead. This has
various benefits, including that we can expose these values directly as
D-Bus properties, and also that the values parse the same in all cases.

1 files changed, 10 insertions, 0 deletions

diff --git a/CODING_STYLE b/CODING_STYLE
index f13f9becbc..98d99dcdaa 100644
--- a/CODING_STYLE
+++ b/CODING_STYLE
@@ -311,3 +311,13 @@
   always-true expression for an infinite while() loop is our
   recommendation is to simply write it without any such expression by
   using "for (;;)".
+
+- Never use the "off_t" type, and particularly avoid it in public
+  APIs. It's really weirdly defined, as it usually is 64bit and we
+  don't support it any other way, but it could in theory also be
+  32bit. Which one it is depends on a compiler switch chosen by the
+  compiled program, which hence corrupts APIs using it unless they can
+  also follow the program's choice. Moreover, in systemd we should
+  parse values the same way on all architectures and cannot expose
+  off_t values over D-Bus. To avoid any confusion regarding conversion
+  and ABIs, always use simply uint64_t directly.