os: complain about unsupported pnprintf directives

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Keith Packard <keithp@keithp.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/os/log.c b/os/log.c
index 9f95743b5..3dc675f5c 100644
--- a/os/log.c
+++ b/os/log.c
@@ -461,6 +461,7 @@ pnprintf(char *string, size_t size, const char *f, va_list args)
             string[s_idx++] = '%';
             break;
         default:
+            BUG_WARN_MSG(f[f_idx], "Unsupported printf directive '%c'\n", f[f_idx]);
             va_arg(args, char*);
             string[s_idx++] = '%';
             if (s_idx < size - 1)