build: silence -Wunused-result

For clang, it's enough to just put (void) around usages we are
intentionally ignoring the result of.

Since GCC does not seem to want to respect this decision, we are forced
to disable the warning globally.

10 files changed, 19 insertions, 17 deletions

diff --git a/audio/out/ao_oss.c b/audio/out/ao_oss.c
index 393c9db780..3216d673e1 100644
--- a/audio/out/ao_oss.c
+++ b/audio/out/ao_oss.c
@@ -462,7 +462,7 @@ static int init(struct ao *ao)
         p->buffersize = 0;
         memset(data, 0, p->outburst);
         while (p->buffersize < 0x40000 && device_writable(ao) > 0) {
-            write(p->audio_fd, data, p->outburst);
+            (void)write(p->audio_fd, data, p->outburst);
             p->buffersize += p->outburst;
         }
         free(data);
diff --git a/audio/out/push.c b/audio/out/push.c
index 4fa2bc53d5..6884702108 100644
--- a/audio/out/push.c
+++ b/audio/out/push.c
@@ -489,7 +489,7 @@ int ao_wait_poll(struct ao *ao, struct pollfd *fds, int num_fds,
         // flush the wakeup pipe contents - might "drown" some wakeups, but
         // that's ok for our use-case
         char buf[100];
-        read(p->wakeup_pipe[0], buf, sizeof(buf));
+        (void)read(p->wakeup_pipe[0], buf, sizeof(buf));
     }
     return (r >= 0 || r == -EINTR) ? wakeup : -1;
 }
@@ -499,7 +499,7 @@ void ao_wakeup_poll(struct ao *ao)
     assert(ao->api == &ao_api_push);
     struct ao_push_state *p = ao->api_priv;
 
-    write(p->wakeup_pipe[1], &(char){0}, 1);
+    (void)write(p->wakeup_pipe[1], &(char){0}, 1);
 }
 
 #endif
diff --git a/input/ipc-unix.c b/input/ipc-unix.c
index 8b8a158c5f..12d7018c9e 100644
--- a/input/ipc-unix.c
+++ b/input/ipc-unix.c
@@ -134,7 +134,7 @@ static void *client_thread(void *p)
 
         if (fds[0].revents & POLLIN) {
             char discard[100];
-            read(pipe_fd, discard, sizeof(discard));
+            (void)read(pipe_fd, discard, sizeof(discard));
 
             while (1) {
                 mpv_event *event = mpv_wait_event(arg->client, 0);
@@ -413,7 +413,7 @@ void mp_uninit_ipc(struct mp_ipc_ctx *arg)
     if (!arg)
         return;
 
-    write(arg->death_pipe[1], &(char){0}, 1);
+    (void)write(arg->death_pipe[1], &(char){0}, 1);
     pthread_join(arg->thread, NULL);
 
     close(arg->death_pipe[0]);
diff --git a/osdep/terminal-unix.c b/osdep/terminal-unix.c
index 3c2784bacd..e62903055a 100644
--- a/osdep/terminal-unix.c
+++ b/osdep/terminal-unix.c
@@ -275,7 +275,7 @@ static void enable_kx(bool enable)
     // shouldn't be relied on here either.
     if (isatty(STDOUT_FILENO)) {
         char *cmd = enable ? "\033=" : "\033>";
-        write(STDOUT_FILENO, cmd, strlen(cmd));
+        (void)write(STDOUT_FILENO, cmd, strlen(cmd));
     }
 }
 
@@ -378,7 +378,7 @@ static void quit_request_sighandler(int signum)
 {
     do_deactivate_getch2();
 
-    write(death_pipe[1], &(char){0}, 1);
+    (void)write(death_pipe[1], &(char){0}, 1);
 }
 
 static void *terminal_thread(void *ptr)
@@ -450,7 +450,7 @@ void terminal_uninit(void)
     do_deactivate_getch2();
 
     if (input_ctx) {
-        write(death_pipe[1], &(char){0}, 1);
+        (void)write(death_pipe[1], &(char){0}, 1);
         pthread_join(input_thread, NULL);
         close(death_pipe[0]);
         close(death_pipe[1]);
diff --git a/player/client.c b/player/client.c
index 45bd2297ba..f5a321b41d 100644
--- a/player/client.c
+++ b/player/client.c
@@ -280,7 +280,7 @@ static void wakeup_client(struct mpv_handle *ctx)
         if (ctx->wakeup_cb)
             ctx->wakeup_cb(ctx->wakeup_cb_ctx);
         if (ctx->wakeup_pipe[0] != -1)
-            write(ctx->wakeup_pipe[1], &(char){0}, 1);
+            (void)write(ctx->wakeup_pipe[1], &(char){0}, 1);
     }
     pthread_mutex_unlock(&ctx->wakeup_lock);
 }
@@ -1559,7 +1559,7 @@ int mpv_get_wakeup_pipe(mpv_handle *ctx)
     pthread_mutex_lock(&ctx->wakeup_lock);
     if (ctx->wakeup_pipe[0] == -1) {
         if (mp_make_wakeup_pipe(ctx->wakeup_pipe) >= 0)
-            write(ctx->wakeup_pipe[1], &(char){0}, 1);
+            (void)write(ctx->wakeup_pipe[1], &(char){0}, 1);
     }
     int fd = ctx->wakeup_pipe[0];
     pthread_mutex_unlock(&ctx->wakeup_lock);
diff --git a/player/playloop.c b/player/playloop.c
index 4e6910fc31..56701dbc34 100644
--- a/player/playloop.c
+++ b/player/playloop.c
@@ -612,7 +612,7 @@ static void handle_heartbeat_cmd(struct MPContext *mpctx)
         double now = mp_time_sec();
         if (mpctx->next_heartbeat <= now) {
             mpctx->next_heartbeat = now + opts->heartbeat_interval;
-            system(opts->heartbeat_cmd);
+            (void)system(opts->heartbeat_cmd);
         }
         mpctx->sleeptime = MPMIN(mpctx->sleeptime, mpctx->next_heartbeat - now);
     }
diff --git a/stream/stream.c b/stream/stream.c
index 5e57ff701d..846765f326 100644
--- a/stream/stream.c
+++ b/stream/stream.c
@@ -978,7 +978,7 @@ struct mp_cancel *mp_cancel_new(void *talloc_ctx)
 void mp_cancel_trigger(struct mp_cancel *c)
 {
     atomic_store(&c->triggered, true);
-    write(c->wakeup_pipe[1], &(char){0}, 1);
+    (void)write(c->wakeup_pipe[1], &(char){0}, 1);
 }
 
 // Restore original state. (Allows reusing a mp_cancel.)
diff --git a/video/out/drm_common.c b/video/out/drm_common.c
index c105a1463f..a39db93617 100644
--- a/video/out/drm_common.c
+++ b/video/out/drm_common.c
@@ -222,7 +222,7 @@ void kms_destroy(struct kms *kms)
 static void vt_switcher_sighandler(int sig)
 {
     unsigned char event = sig == RELEASE_SIGNAL ? EVT_RELEASE : EVT_ACQUIRE;
-    write(vt_switcher_pipe[1], &event, sizeof(event));
+    (void)write(vt_switcher_pipe[1], &event, sizeof(event));
 }
 
 static bool has_signal_installed(int signo)
@@ -312,7 +312,7 @@ void vt_switcher_release(struct vt_switcher *s,
 void vt_switcher_interrupt_poll(struct vt_switcher *s)
 {
     unsigned char event = EVT_INTERRUPT;
-    write(vt_switcher_pipe[1], &event, sizeof(event));
+    (void)write(vt_switcher_pipe[1], &event, sizeof(event));
 }
 
 void vt_switcher_destroy(struct vt_switcher *s)
diff --git a/video/out/vo.c b/video/out/vo.c
index 29b1baabdd..07476ad7c3 100644
--- a/video/out/vo.c
+++ b/video/out/vo.c
@@ -596,14 +596,14 @@ static void wait_event_fd(struct vo *vo, int64_t until_time)
 
     if (fds[1].revents & POLLIN) {
         char buf[100];
-        read(in->wakeup_pipe[0], buf, sizeof(buf)); // flush
+        (void)read(in->wakeup_pipe[0], buf, sizeof(buf)); // flush
     }
 }
 static void wakeup_event_fd(struct vo *vo)
 {
     struct vo_internal *in = vo->in;
 
-    write(in->wakeup_pipe[1], &(char){0}, 1);
+    (void)write(in->wakeup_pipe[1], &(char){0}, 1);
 }
 #else
 static void wait_event_fd(struct vo *vo, int64_t until_time){}
diff --git a/waftools/detections/compiler.py b/waftools/detections/compiler.py
index ada20796b1..5c4b680343 100644
--- a/waftools/detections/compiler.py
+++ b/waftools/detections/compiler.py
@@ -41,7 +41,9 @@ def __add_generic_flags__(ctx):
 def __add_gcc_flags__(ctx):
     ctx.env.CFLAGS += ["-Wall", "-Wundef", "-Wmissing-prototypes", "-Wshadow",
                        "-Wno-switch", "-Wparentheses", "-Wpointer-arith",
-                       "-Wno-pointer-sign"]
+                       "-Wno-pointer-sign",
+                       # GCC bug 66425
+                       "-Wno-unused-result"]
 
 def __add_clang_flags__(ctx):
     ctx.env.CFLAGS += ["-Wno-logical-op-parentheses", "-fcolor-diagnostics",