[glib/wip/smcv/none-flags: 6/8] giochannel: Add G_IO_FLAG_NONE

[Simon McVittie <smcv src gnome org>]

commit cef780e9ef86b1d9545db892c6b8340488da21d9
Author: Simon McVittie <smcv collabora com>
Date:   Thu Jun 23 10:12:44 2022 +0100

    giochannel: Add G_IO_FLAG_NONE
    
    This makes the state where no flags are set a bit more self-documenting.
    
    Signed-off-by: Simon McVittie <smcv collabora com>

 glib/giochannel.c | 1 +
 glib/giochannel.h | 1 +
 glib/giounix.c    | 2 +-
 3 files changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/glib/giochannel.c b/glib/giochannel.c
index 6fec45f66d..25baf42c9a 100644
--- a/glib/giochannel.c
+++ b/glib/giochannel.c
@@ -946,6 +946,7 @@ g_io_channel_get_line_term (GIOChannel *channel,
  **/
 /**
  * GIOFlags:
+ * @G_IO_FLAG_NONE: no special flags set. Since: 2.74
  * @G_IO_FLAG_APPEND: turns on append mode, corresponds to %O_APPEND
  *     (see the documentation of the UNIX open() syscall)
  * @G_IO_FLAG_NONBLOCK: turns on nonblocking mode, corresponds to
diff --git a/glib/giochannel.h b/glib/giochannel.h
index 5a13449d58..dee3d7d055 100644
--- a/glib/giochannel.h
+++ b/glib/giochannel.h
@@ -85,6 +85,7 @@ typedef enum
 
 typedef enum
 {
+  G_IO_FLAG_NONE GLIB_AVAILABLE_ENUMERATOR_IN_2_74 = 0,
   G_IO_FLAG_APPEND = 1 << 0,
   G_IO_FLAG_NONBLOCK = 1 << 1,
   G_IO_FLAG_IS_READABLE = 1 << 2,      /* Read only flag */
diff --git a/glib/giounix.c b/glib/giounix.c
index b6345b6c68..067cecf9ac 100644
--- a/glib/giounix.c
+++ b/glib/giounix.c
@@ -400,7 +400,7 @@ g_io_unix_set_flags (GIOChannel *channel,
 static GIOFlags
 g_io_unix_get_flags (GIOChannel *channel)
 {
-  GIOFlags flags = 0;
+  GIOFlags flags = G_IO_FLAG_NONE;
   glong fcntl_flags;
   GIOUnixChannel *unix_channel = (GIOUnixChannel *) channel;