[3/8] fsmonitor: mark some maybe-unused parameters

Commit Message

Jeff King Sept. 18, 2023, 10:31 p.m. UTC

There's a bit of conditionally-compiled code in fsmonitor, so some
function parameters may be unused depending on the build options:

  - in fsmonitor--daemon.c's try_to_run_foreground_daemon(), we take a
    detach_console argument, but it's only used on Windows. This seems
    intentional (and not mistakenly missing other platforms) based on
    the discussion in c284e27ba7 (fsmonitor--daemon: implement 'start'
    command, 2022-03-25), which introduced it.

  - in fsmonitor-setting.c's check_for_incompatible(), we pass the "ipc"
    flag down to the system-specific fsm_os__incompatible() helper. But
    we can only do so if our platform has such a helper.

In both cases we can mark the argument as MAYBE_UNUSED. That annotates
it enough to suppress the compiler's -Wunused-parameter warning, but
without making it impossible to use the variable, as a regular UNUSED
annotation would.

Signed-off-by: Jeff King <[e-mail]>
---
For a similar case in 2c3c3d88fc (imap-send: mark unused parameters with
NO_OPENSSL, 2023-08-29), I used the old:

  (void)some_parameter_that_might_not_be_used;

trick. But I realized while writing this one that MAYBE_UNUSED fits the
bill a little more nicely, and I don't see any reason we would have
portability problems with it.

 builtin/fsmonitor--daemon.c | 2 +-
 fsmonitor-settings.c        | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

Patch

diff --git a/builtin/fsmonitor--daemon.c b/builtin/fsmonitor--daemon.c
index 7e99c4d61b..7c4130c981 100644
--- a/builtin/fsmonitor--daemon.c
+++ b/builtin/fsmonitor--daemon.c
@@ -1412,7 +1412,7 @@  static int fsmonitor_run_daemon(void)
 	return err;
 }
 
-static int try_to_run_foreground_daemon(int detach_console)
+static int try_to_run_foreground_daemon(int detach_console MAYBE_UNUSED)
 {
 	/*
 	 * Technically, we don't need to probe for an existing daemon
diff --git a/fsmonitor-settings.c b/fsmonitor-settings.c
index b62acf44ae..a6a9e6bc19 100644
--- a/fsmonitor-settings.c
+++ b/fsmonitor-settings.c
@@ -62,7 +62,8 @@  static enum fsmonitor_reason check_remote(struct repository *r)
 }
 #endif
 
-static enum fsmonitor_reason check_for_incompatible(struct repository *r, int ipc)
+static enum fsmonitor_reason check_for_incompatible(struct repository *r,
+						    int ipc MAYBE_UNUSED)
 {
 	if (!r->worktree) {
 		/*