[PATCH 2/2] Add warn_unused_result attr to AUD_register_card

[Manos Pitsidianakis]

Ignoring the return value by accident is easy to miss as a bug. Such a
bug was spotted by Coverity CID 1523899. Now, future instances of this
type of bug will produce a warning when using GCC.

Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
---
 audio/audio.h      | 2 +-
 hw/arm/omap2.c     | 8 +++++++-
 hw/input/tsc210x.c | 8 +++++++-
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/audio/audio.h b/audio/audio.h
index fcc22307be..b78c75962e 100644
--- a/audio/audio.h
+++ b/audio/audio.h
@@ -94,7 +94,7 @@ typedef struct QEMUAudioTimeStamp {
 void AUD_vlog (const char *cap, const char *fmt, va_list ap) G_GNUC_PRINTF(2, 
0);
 void AUD_log (const char *cap, const char *fmt, ...) G_GNUC_PRINTF(2, 3);
 
-bool AUD_register_card (const char *name, QEMUSoundCard *card, Error **errp);
+bool AUD_register_card (const char *name, QEMUSoundCard *card, Error **errp) 
QEMU_WARN_UNUSED_RESULT;
 void AUD_remove_card (QEMUSoundCard *card);
 CaptureVoiceOut *AUD_add_capture(
     AudioState *s,
diff --git a/hw/arm/omap2.c b/hw/arm/omap2.c
index f170728e7e..59fc061120 100644
--- a/hw/arm/omap2.c
+++ b/hw/arm/omap2.c
@@ -614,7 +614,13 @@ static struct omap_eac_s *omap_eac_init(struct 
omap_target_agent_s *ta,
         s->codec.card.name = g_strdup(current_machine->audiodev);
         s->codec.card.state = audio_state_by_name(s->codec.card.name, 
&error_fatal);
     }
-    AUD_register_card("OMAP EAC", &s->codec.card, &error_fatal);
+    /*
+     * We pass error_fatal so on error QEMU will exit(). But we check the
+     * return value to make the warn_unused_result compiler warning go away.
+     */
+    if (!AUD_register_card("OMAP EAC", &s->codec.card, &error_fatal)) {
+        exit(1);
+    }
 
     memory_region_init_io(&s->iomem, NULL, &omap_eac_ops, s, "omap.eac",
                           omap_l4_region_size(ta, 0));
diff --git a/hw/input/tsc210x.c b/hw/input/tsc210x.c
index 950506fb38..003c664b56 100644
--- a/hw/input/tsc210x.c
+++ b/hw/input/tsc210x.c
@@ -1102,7 +1102,13 @@ static void tsc210x_init(TSC210xState *s,
         s->card.name = g_strdup(current_machine->audiodev);
         s->card.state = audio_state_by_name(s->card.name, &error_fatal);
     }
-    AUD_register_card(s->name, &s->card, &error_fatal);
+    /*
+     * We pass error_fatal so on error QEMU will exit(). But we check the
+     * return value to make the warn_unused_result compiler warning go away.
+     */
+    if (!AUD_register_card(s->name, &s->card, &error_fatal)) {
+        return;
+    }
 
     qemu_register_reset((void *) tsc210x_reset, s);
     vmstate_register(NULL, 0, vmsd, s);
-- 
2.39.2