Fix wait loop and void cast (#24)

* Simplify EINTR/ECANCEL error handling

1. Add semaphore uninterruptible wait function
2 .Replace semaphore wait loop with a single uninterruptible wait
3. Replace all sem_xxx to nxsem_xxx

* Unify the void cast usage

1. Remove void cast for function because many place ignore the returned value witout cast
2. Replace void cast for variable with UNUSED macro

graphics/nxglib/lcd/nxglib_copyrectangle.c

@@ -100,7 +100,7 @@ void NXGL_FUNCNAME(nxgl_copyrectangle, NXGLIB_SUFFIX)
       if (remainder != 0)
         {
           NXGL_FUNCNAME(nxgl_copyrun, NXGLIB_SUFFIX)(sline, pinfo->buffer, remainder, ncols);
-          (void)pinfo->putrun(row, dest->pt1.x, pinfo->buffer, ncols);
+          pinfo->putrun(row, dest->pt1.x, pinfo->buffer, ncols);
         }
       else
 #endif
@@ -109,7 +109,7 @@ void NXGL_FUNCNAME(nxgl_copyrectangle, NXGLIB_SUFFIX)
            * the image memory.
            */
 
-          (void)pinfo->putrun(row, dest->pt1.x, sline, ncols);
+          pinfo->putrun(row, dest->pt1.x, sline, ncols);
         }
 
       /* Then adjust the source pointer to refer to the next line in the source

graphics/nxglib/lcd/nxglib_fillrectangle.c

@@ -90,6 +90,6 @@ void NXGL_FUNCNAME(nxgl_fillrectangle, NXGLIB_SUFFIX)
     {
       /* Draw the raster line at this row */
 
-      (void)pinfo->putrun(row, rect->pt1.x, pinfo->buffer, ncols);
+      pinfo->putrun(row, rect->pt1.x, pinfo->buffer, ncols);
     }
 }

graphics/nxglib/lcd/nxglib_filltrapezoid.c

@@ -232,7 +232,7 @@ void NXGL_FUNCNAME(nxgl_filltrapezoid, NXGLIB_SUFFIX)
           /* Then draw the run from ix1 to ix2 at row */
 
           ncols = ix2 - ix1 + 1;
-          (void)pinfo->putrun(row, ix1, pinfo->buffer, ncols);
+          pinfo->putrun(row, ix1, pinfo->buffer, ncols);
         }
 
       /* Add the dx/dy value to get the run positions on the next row */

graphics/nxglib/lcd/nxglib_getrectangle.c

@@ -79,7 +79,7 @@ void NXGL_FUNCNAME(nxgl_getrectangle, NXGLIB_SUFFIX)
 
   for (srcrow = rect->pt1.y; srcrow <= rect->pt2.y; srcrow++)
     {
-      (void)pinfo->getrun(srcrow, rect->pt1.x, dline, ncols);
+      pinfo->getrun(srcrow, rect->pt1.x, dline, ncols);
       dline += deststride;
     }
 }

graphics/nxglib/lcd/nxglib_moverectangle.c

@@ -85,8 +85,8 @@ void NXGL_FUNCNAME(nxgl_moverectangle, NXGLIB_SUFFIX)
            srcrow <= rect->pt2.y;
            srcrow++, destrow++)
         {
-          (void)pinfo->getrun(srcrow, rect->pt1.x, pinfo->buffer, ncols);
-          (void)pinfo->putrun(destrow, offset->x, pinfo->buffer, ncols);
+          pinfo->getrun(srcrow, rect->pt1.x, pinfo->buffer, ncols);
+          pinfo->putrun(destrow, offset->x, pinfo->buffer, ncols);
         }
     }
 
@@ -104,8 +104,8 @@ void NXGL_FUNCNAME(nxgl_moverectangle, NXGLIB_SUFFIX)
            srcrow >= rect->pt1.y;
            srcrow--, destrow--)
         {
-          (void)pinfo->getrun(srcrow, rect->pt1.x, pinfo->buffer, ncols);
-          (void)pinfo->putrun(destrow, offset->x, pinfo->buffer, ncols);
+          pinfo->getrun(srcrow, rect->pt1.x, pinfo->buffer, ncols);
+          pinfo->putrun(destrow, offset->x, pinfo->buffer, ncols);
         }
     }
 }

graphics/nxglib/lcd/nxglib_setpixel.c

@@ -81,7 +81,7 @@ void NXGL_FUNCNAME(nxgl_setpixel, NXGLIB_SUFFIX)
 
   /* Read the byte that contains the pixel to be changed */
 
-  (void)pinfo->getrun(pos->y, pos->x, &pixel, 8 / NXGLIB_BITSPERPIXEL);
+  pinfo->getrun(pos->y, pos->x, &pixel, 8 / NXGLIB_BITSPERPIXEL);
 
   /* Shift the color into the proper position */
 
@@ -128,10 +128,10 @@ void NXGL_FUNCNAME(nxgl_setpixel, NXGLIB_SUFFIX)
 
   /* Write the modified byte back to graphics memory */
 
-  (void)pinfo->putrun(pos->y, pos->x, (FAR uint8_t *)&pixel, 8 / NXGLIB_BITSPERPIXEL);
+  pinfo->putrun(pos->y, pos->x, (FAR uint8_t *)&pixel, 8 / NXGLIB_BITSPERPIXEL);
 #else
   /* Draw a single pixel at this position raster line at this row */
 
-  (void)pinfo->putrun(pos->y, pos->x, (FAR uint8_t *)&color, 1);
+  pinfo->putrun(pos->y, pos->x, (FAR uint8_t *)&color, 1);
 #endif
 }

graphics/nxmu/nxmu_kbdin.c

@@ -90,7 +90,7 @@ void nxmu_kbdin(FAR struct nxmu_state_s *nxmu, uint8_t nch, FAR uint8_t *ch)
           outmsg->ch[i] = ch[i];
         }
 
-      (void)nxmu_sendclientwindow(nxmu->be.topwnd, outmsg, size);
+      nxmu_sendclientwindow(nxmu->be.topwnd, outmsg, size);
       kmm_free(outmsg);
     }
 }

graphics/nxmu/nxmu_redraw.c

@@ -150,8 +150,8 @@ void nxmu_redrawreq(FAR struct nxbe_window_s *wnd,
   nxgl_rectoffset(&outmsg.rect, rect,
                   -wnd->bounds.pt1.x, -wnd->bounds.pt1.y);
 
-  (void)nxmu_sendclientwindow(wnd, &outmsg,
-                              sizeof(struct nxclimsg_redraw_s));
+  nxmu_sendclientwindow(wnd, &outmsg,
+                        sizeof(struct nxclimsg_redraw_s));
 }
 
 /****************************************************************************

graphics/nxmu/nxmu_server.c

@@ -79,7 +79,7 @@ static inline void nxmu_disconnect(FAR struct nxmu_conn_s *conn)
 
   /* Close the outgoing client message queue */
 
-  (void)mq_close(conn->swrmq);
+  mq_close(conn->swrmq);
 }
 
 /****************************************************************************
@@ -133,7 +133,7 @@ static inline void nxmu_shutdown(FAR struct nxmu_state_s *nxmu)
 
   for (wnd = nxmu->be.topwnd; wnd; wnd = wnd->below)
     {
-       (void)nxmu_disconnect(wnd->conn);
+       nxmu_disconnect(wnd->conn);
     }
 }
 

graphics/nxmu/nxmu_start.c

@@ -119,7 +119,7 @@ static int nx_server(int argc, char *argv[])
 
   /* Turn the LCD on at 75% power */
 
-  (void)dev->setpower(dev, ((3 * CONFIG_LCD_MAXPOWER + 3) / 4));
+  dev->setpower(dev, ((3 * CONFIG_LCD_MAXPOWER + 3) / 4));
 
 #else /* CONFIG_NX_LCDDRIVER */
   /* Initialize the frame buffer device. */

graphics/nxterm/nxterm_putc.c

@@ -183,5 +183,5 @@ void nxterm_showcursor(FAR struct nxterm_state_s *priv)
 
 void nxterm_hidecursor(FAR struct nxterm_state_s *priv)
 {
-  (void)nxterm_hidechar(priv, &priv->cursor);
+  nxterm_hidechar(priv, &priv->cursor);
 }

graphics/nxterm/nxterm_redraw.c

@@ -94,17 +94,6 @@ void nxterm_redraw(NXTERM handle, FAR const struct nxgl_rect_s *rect, bool more)
   do
     {
       ret = nxterm_semwait(priv);
-
-      /* Check for errors */
-
-      if (ret < 0)
-        {
-          /* The only expected error is if the wait failed because of it
-           * was interrupted by a signal.
-           */
-
-          DEBUGASSERT(ret == -EINTR || ret == -ECANCELED);
-        }
     }
   while (ret < 0);
 
@@ -125,5 +114,5 @@ void nxterm_redraw(NXTERM handle, FAR const struct nxgl_rect_s *rect, bool more)
       nxterm_fillchar(priv, rect, &priv->bm[i]);
     }
 
-  (void)nxterm_sempost(priv);
+  nxterm_sempost(priv);
 }

graphics/nxterm/nxterm_resize.c

@@ -88,11 +88,6 @@ int nxterm_resize(NXTERM handle, FAR const struct nxgl_size_s *size)
   ret = nxterm_semwait(priv);
   if (ret < 0)
     {
-      /* The only expected error is if the wait failed because of it was
-       * interrupted by a signal or if the thread was canceled.
-       */
-
-      DEBUGASSERT(ret == -EINTR || ret == -ECANCELED);
       return ret;
     }
 
@@ -103,6 +98,6 @@ int nxterm_resize(NXTERM handle, FAR const struct nxgl_size_s *size)
   priv->wndo.wsize.w = size->w;
   priv->wndo.wsize.h = size->h;
 
-  (void)nxterm_sempost(priv);
+  nxterm_sempost(priv);
   return true;
 }

graphics/nxterm/nxterm_unregister.c

@@ -90,7 +90,7 @@ void nxterm_unregister(FAR struct nxterm_state_s *priv)
   /* Unregister the driver */
 
   snprintf(devname, NX_DEVNAME_SIZE, NX_DEVNAME_FORMAT, priv->minor);
-  (void)unregister_driver(devname);
+  unregister_driver(devname);
 
   /* Free the private data structure */
 

graphics/vnc/server/vnc_fbdev.c

@@ -452,7 +452,7 @@ static int vnc_start_server(int display)
 
   /* Format the kernel thread arguments (ASCII.. yech) */
 
-  (void)itoa(display, str, 10);
+  itoa(display, str, 10);
   argv[0] = str;
   argv[1] = NULL;
 
@@ -486,8 +486,6 @@ static int vnc_start_server(int display)
 
 static inline int vnc_wait_start(int display)
 {
-  int ret = OK;
-
   /* Check if there has been a session allocated yet.  This is one of the
    * first things that the VNC server will do with the kernel thread is
    * started.  But we might be here before the thread has gotten that far.
@@ -506,20 +504,10 @@ static inline int vnc_wait_start(int display)
        * conditions here, but I think none that are fatal.
        */
 
-      do
-        {
-          ret = nxsem_wait(&g_fbstartup[display].fbinit);
-
-          /* The only case that an error should occur here is if the wait
-           * was awakened by a signal.
-           */
-
-          DEBUGASSERT(ret == OK || ret == -EINTR);
-        }
-      while (ret == -EINTR);
+      nxsem_wait_uninterruptible(&g_fbstartup[display].fbinit);
     }
 
-  return ret;
+  return OK;
 }
 
 /****************************************************************************
@@ -564,20 +552,11 @@ static inline int vnc_wait_connect(int display)
        * conditions here, but I think none that are fatal.
        */
 
-      do
+      ret = nxsem_wait_uninterruptible(&g_fbstartup[display].fbconnect);
+      if (ret < 0)
         {
-          ret = nxsem_wait(&g_fbstartup[display].fbconnect);
-
-          /* The only case that an error should occur here is if the wait
-           * was awakened by a signal.
-           */
-
-          if (ret < 0 && ret != -EINTR)
-            {
-              return ret;
-            }
+          return ret;
         }
-      while (ret == -EINTR);
 
       /* We were awakened.  A result of -EBUSY means that the negotiation
        * is not complete.  Why would we be awakened in that case?  Some

graphics/vnc/server/vnc_keymap.c

@@ -648,7 +648,7 @@ void vnc_key_map(FAR struct vnc_session_s *session, uint16_t keysym,
 void vnc_kbdout(FAR void *arg, uint8_t nch, FAR const uint8_t *ch)
 {
   DEBUGASSERT(arg != NULL);
-  (void)nx_kbdin((NXHANDLE)arg, nch, ch);
+  nx_kbdin((NXHANDLE)arg, nch, ch);
 }
 
 #endif /* CONFIG_NX_KBD */

graphics/vnc/server/vnc_receiver.c

@@ -516,6 +516,6 @@ void vnc_mouseout(FAR void *arg, nxgl_coord_t x, nxgl_coord_t y,
                   uint8_t buttons)
 {
   DEBUGASSERT(arg != NULL);
-  (void)nx_mousein((NXHANDLE)arg, x, y, buttons);
+  nx_mousein((NXHANDLE)arg, x, y, buttons);
 }
 #endif

graphics/vnc/server/vnc_updater.c

@@ -129,21 +129,8 @@ static void vnc_sem_debug(FAR struct vnc_session_s *session,
   int queuecount;
   int freewaiting;
   int queuewaiting;
-  int ret;
 
-  do
-    {
-      /* Take the semaphore (perhaps waiting) */
-
-      ret = nxsem_wait(&g_errsem);
-
-      /* The only case that an error should occur here is if the wait was
-       * awakened by a signal.
-       */
-
-      DEBUGASSERT(ret == OK || ret == -EINTR);
-    }
-  while (ret == -EINTR);
+  nxsem_wait_uninterruptible(&g_errsem);
 
   /* Count structures in the list */
 
@@ -207,7 +194,6 @@ static FAR struct vnc_fbupdate_s *
 vnc_alloc_update(FAR struct vnc_session_s *session)
 {
   FAR struct vnc_fbupdate_s *update;
-  int ret;
 
   /* Reserve one element from the free list.  Lock the scheduler to assure
    * that the sq_remfirst() and the successful return from nxsem_wait are
@@ -217,19 +203,7 @@ vnc_alloc_update(FAR struct vnc_session_s *session)
   sched_lock();
   vnc_sem_debug(session, "Before alloc", 0);
 
-  do
-    {
-      /* Take the semaphore (perhaps waiting) */
-
-      ret = nxsem_wait(&session->freesem);
-
-      /* The only case that an error should occur here is if the wait was
-       * awakened by a signal.
-       */
-
-      DEBUGASSERT(ret == OK || ret == -EINTR);
-    }
-  while (ret == -EINTR);
+  nxsem_wait_uninterruptible(&session->freesem);
 
   /* It is reserved.. go get it */
 
@@ -300,7 +274,6 @@ static FAR struct vnc_fbupdate_s *
 vnc_remove_queue(FAR struct vnc_session_s *session)
 {
   FAR struct vnc_fbupdate_s *rect;
-  int ret;
 
   /* Reserve one element from the list of queued rectangle.  Lock the
    * scheduler to assure that the sq_remfirst() and the successful return
@@ -311,19 +284,7 @@ vnc_remove_queue(FAR struct vnc_session_s *session)
   sched_lock();
   vnc_sem_debug(session, "Before remove", 0);
 
-  do
-    {
-      /* Take the semaphore (perhaps waiting) */
-
-      ret = nxsem_wait(&session->queuesem);
-
-      /* The only case that an error should occur here is if the wait was
-       * awakened by a signal.
-       */
-
-      DEBUGASSERT(ret == OK || ret == -EINTR);
-    }
-  while (ret == -EINTR);
+  nxsem_wait_uninterruptible(&session->queuesem);
 
   /* It is reserved.. go get it */