master 250a5e8bdd 3/5: Pacify Oracle Studio re xterm.c

[Paul Eggert]

branch: master
commit 250a5e8bdde09c7e7d67bc006c469964de7474bb
Author: Paul Eggert <eggert@cs.ucla.edu>
Commit: Paul Eggert <eggert@cs.ucla.edu>

    Pacify Oracle Studio re xterm.c
    
    * src/xterm.c (xErrorHandler,  xIOErrorHandler):
    New typedefs.
    (xm_get_drag_window_1, x_connection_closed): Use them instead of
    void *, since the C standard frowns on converting function
    pointers to and from void *.  This pacifies Oracle Studio
    diagnostics like “warning: assignment type mismatch: pointer to
    void "=" pointer to function(pointer to struct _XDisplay {})\
    returning int”.
    (x_detect_pending_selection_requests, x_had_errors_p): Do not rely
    on implicit conversion of a pointer to a bool return value; use !!
    instead.  This pacifies Oracle Studio’s “warning: improper
    pointer/integer combination: op "="”.
    (xim_open_dpy) [HAVE_X11R6 && !HAVE_X11R6_XIM]: Do not use
    xim_destroy_callback; configure.ac says “inoue@ainet.or.jp says
    Solaris has a bug related to X11R6-style ## XIM support” and
    Oracle Studio complains “warning: assignment type mismatch:
    pointer to function(pointer to struct _XIC {}, pointer to char,
    pointer\ to char) returning void "=" pointer to function(pointer
    to struct _XIM {}, pointer to char, pointer to char) returning
    void”.
---
 src/xterm.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/xterm.c b/src/xterm.c
index 7d5794bdd7..cd9645af07 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -719,6 +719,12 @@ along with GNU Emacs.  If not, see 
<https://www.gnu.org/licenses/>.  */
 #include <X11/XKBlib.h>
 #endif
 
+/* Although X11/Xlib.h commonly defines the types XErrorHandler and
+   XIOErrorHandler, they are not in the Xlib spec so for portability
+   define and use names with a leading lower-case 'x' instead.  */
+typedef int (*xErrorHandler) (Display *, XErrorEvent *);
+typedef int (*xIOErrorHandler) (Display *);
+
 #if defined USE_XCB && defined USE_CAIRO_XCB
 #define USE_CAIRO_XCB_SURFACE
 #endif
@@ -1830,7 +1836,9 @@ xm_get_drag_window_1 (struct x_display_info *dpyinfo)
   Window drag_window;
   XSetWindowAttributes attrs;
   Display *temp_display;
-  void *old_handler, *old_io_handler;
+  xErrorHandler old_handler;
+  xIOErrorHandler old_io_handler;
+
   /* These are volatile because GCC mistakenly warns about them being
      clobbered by longjmp.  */
   volatile bool error, created;
@@ -1893,9 +1901,7 @@ xm_get_drag_window_1 (struct x_display_info *dpyinfo)
       XGrabServer (temp_display);
       XSetCloseDownMode (temp_display, RetainPermanent);
 
-      /* We can't use XErrorHandler since it's not in the Xlib
-        specification, and Emacs tries to be portable.  */
-      old_handler = (void *) XSetErrorHandler (xm_drag_window_error_handler);
+      old_handler = XSetErrorHandler (xm_drag_window_error_handler);
 
       _MOTIF_DRAG_WINDOW = XInternAtom (temp_display,
                                        "_MOTIF_DRAG_WINDOW", False);
@@ -11202,7 +11208,7 @@ x_push_selection_request (struct selection_input_event 
*se)
 bool
 x_detect_pending_selection_requests (void)
 {
-  return pending_selection_requests;
+  return !!pending_selection_requests;
 }
 
 static void
@@ -23024,7 +23030,7 @@ x_had_errors_p (Display *dpy)
          > x_error_message->first_request))
     XSync (dpy, False);
 
-  return x_error_message->string;
+  return !!x_error_message->string;
 }
 
 /* Forget about any errors we have had, since we did x_catch_errors on
@@ -23084,7 +23090,7 @@ x_connection_closed (Display *dpy, const char 
*error_message, bool ioerror)
   struct x_display_info *dpyinfo;
   Lisp_Object frame, tail;
   specpdl_ref idx = SPECPDL_INDEX ();
-  void *io_error_handler;
+  xIOErrorHandler io_error_handler;
   xm_drop_start_message dmsg;
   struct frame *f;
 
@@ -23479,14 +23485,14 @@ xim_open_dpy (struct x_display_info *dpyinfo, char 
*resource_name)
 
       if (xim)
        {
-#ifdef HAVE_X11R6
+#ifdef HAVE_X11R6_XIM
          XIMCallback destroy;
 #endif
 
          /* Get supported styles and XIM values.  */
          XGetIMValues (xim, XNQueryInputStyle, &dpyinfo->xim_styles, NULL);
 
-#ifdef HAVE_X11R6
+#ifdef HAVE_X11R6_XIM
          destroy.callback = xim_destroy_callback;
          destroy.client_data = (XPointer)dpyinfo;
          XSetIMValues (xim, XNDestroyCallback, &destroy, NULL);