rom/intuition/nextpubscreen.c

   1 /*
   2     Copyright © 1995-2003, The AROS Development Team. All rights reserved.
   3     Copyright © 2001-2003, The MorphOS Development Team. All Rights Reserved.
   4     $Id$
   5 */
   6
   7 #include <string.h>
   8 #include "intuition_intern.h"
   9
  10 /*****************************************************************************
  11
  12     NAME */
  13 #include <proto/intuition.h>
  14
  15 AROS_LH2(UBYTE *, NextPubScreen,
  16
  17          /*  SYNOPSIS */
  18          AROS_LHA(struct Screen *, screen  , A0),
  19          AROS_LHA(UBYTE *        , namebuff, A1),
  20
  21          /*  LOCATION */
  22          struct IntuitionBase *, IntuitionBase, 89, Intuition)
  23
  24 /*  FUNCTION
  25
  26     Gets the next public screen in the system; this allows visitor windows
  27     to jump among public screens in a cycle.
  28
  29     INPUTS
  30
  31     screen    --  Pointer to the public screen your window is open in or
  32                   NULL if you don't have a pointer to a public screen.
  33     namebuff  --  Pointer to a buffer with (at least) MAXPUBSCREENNAME+1
  34                   characters to put the name of the next public screen in.
  35
  36     RESULT
  37
  38     Returns 'namebuff' or NULL if there are no public screens.
  39
  40     NOTES
  41
  42     We cannot guarantee that the public screen, the name of which you got
  43     by using this function, is available when you call for instance
  44     LockPubScreen(). Therefore you must be prepared to handle failure of
  45     that kind of functions.
  46         This function may return the name of a public screen which is in
  47     private mode.
  48         The cycle order is undefined, so draw no conclusions based on it!
  49
  50     EXAMPLE
  51
  52     BUGS
  53
  54     SEE ALSO
  55
  56     OpenScreen(), PubScreenStatus()
  57
  58     INTERNALS
  59
  60     Maybe we should correct the + 1 stupidity right away?
  61
  62 *****************************************************************************/
  63 #define GPB(x) GetPrivIBase(x)
  64
  65 {
  66     AROS_LIBFUNC_INIT
  67     AROS_LIBBASE_EXT_DECL(struct IntuitionBase *,IntuitionBase)
  68
  69     struct PubScreenNode *ps;
  70     struct IntScreen     *scr = (struct IntScreen *)screen;
  71     struct List          *list;
  72
  73     list = LockPubScreenList();
  74
  75     if(scr == NULL)
  76     {
  77         ps = (struct PubScreenNode *)list->lh_Head;
  78         ASSERT(ps != NULL);
  79     }
  80     else
  81     {
  82         ps = scr->pubScrNode;
  83         if (!ps) return NULL;
  84
  85         ps = (struct PubScreenNode *)ps->psn_Node.ln_Succ;
  86         ASSERT(ps != NULL);
  87     }
  88
  89     /* A "valid" node in a list must have ln_Succ != NULL */
  90
  91     if (!ps->psn_Node.ln_Succ) return NULL;
  92
  93     if (namebuff) strcpy(namebuff, ps->psn_Node.ln_Name);
  94
  95     UnlockPubScreenList();
  96
  97     return namebuff;
  98
  99     AROS_LIBFUNC_EXIT
 100 } /* NextPubScreen */