[geany/geany] 09b155: Silence warnings on appropriate GSourceFunc casts - Commits

16 Nov 2023


      Branch:      refs/heads/master
Author:      Colomban Wendling ban@herbesfolles.org
Committer:   Colomban Wendling ban@herbesfolles.org
Date:        Thu, 16 Nov 2023 09:56:02 UTC
Commit:      09b1558d3496a193d2efdd2f99adcb321743fffb
             https://github.com/geany/geany/commit/09b1558d3496a193d2efdd2f99adcb321743ff...
Log Message:
-----------
Silence warnings on appropriate GSourceFunc casts
`g_source_set_callback()` is a generic API that takes a `GFunc`, but
some specific `GSource`s use other signatures for their callback, so
the cast is valid (given the callback is effectively correct).
Silence warnings from `-Wcast-function-type` by inserting an
intermediate `(void(*)(void))` cast, but keep some type checking by
first casting to the actually wanted type:
(GSourceFunc) (void(*)(void)) (GChildWatchFunc) spawn_watch_cb
which reads from right to left:
- `spawn_watch_cb`, the callback that should match `GChildWatchFunc`;
- `(GChildWatchFunc)`, which allows the compiler to verify the function
  is effectively compatible with what we know it should be;
- `(void(*)(void))`, dummy cast to silence `-Wcast-function-type`;
- `(GSourceFunc)`, cast to the type expected by the generic API call.
We could use GLib's `G_SOURCE_FUNC()` cast macro to some extent
(everything but the rightmost cast), but it's in 2.58 which is newer
than our target.
Modified Paths:
--------------
    src/spawn.c
Modified: src/spawn.c
10 lines changed, 5 insertions(+), 5 deletions(-)
===================================================================
@@ -1185,7 +1185,7 @@ gboolean spawn_with_callbacks(const gchar *working_directory, const gchar *comma
    	{
    		SpawnChannelData *sc = &sw->sc[i];
    		GIOCondition condition;
-			GSourceFunc callback;
+			GIOFunc callback;
if (pipe[i] == -1)
    			continue;
@@ -1205,15 +1205,15 @@ gboolean spawn_with_callbacks(const gchar *working_directory, const gchar *comma
    		{
    			sc->cb.write = stdin_cb;
    			condition = G_IO_OUT | SPAWN_IO_FAILURE;
-				callback = (GSourceFunc) spawn_write_cb;
+				callback = spawn_write_cb;
    		}
    		else
    		{
    			gboolean line_buffered = !(spawn_flags &
    				((SPAWN_STDOUT_UNBUFFERED >> 1) << i));
condition = G_IO_IN | G_IO_PRI | SPAWN_IO_FAILURE;
-				callback = (GSourceFunc) spawn_read_cb;
+				callback = spawn_read_cb;
if (i == 1)
    			{
@@ -1245,15 +1245,15 @@ gboolean spawn_with_callbacks(const gchar *working_directory, const gchar *comma
    		else if (i)  /* to avoid new string on each call */
    			sc->buffer = g_string_sized_new(sc->max_length);
-			g_source_set_callback(source, callback, sc, spawn_destroy_cb);
+			g_source_set_callback(source, (GSourceFunc) (void(*)(void)) callback, sc, spawn_destroy_cb);
    		g_source_attach(source, sw->main_context);
    		g_source_unref(source);
    	}
sw->exit_cb = exit_cb;
    	sw->exit_data = exit_data;
    	source = g_child_watch_source_new(pid);
-		g_source_set_callback(source, (GSourceFunc) spawn_watch_cb, sw, NULL);
+		g_source_set_callback(source, (GSourceFunc) (void(*)(void)) (GChildWatchFunc) spawn_watch_cb, sw, NULL);
    	g_source_attach(source, sw->main_context);
    	g_source_unref(source);
--------------
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