xpaconvert(7)							SAORD Documentation						     xpaconvert(7)

NAME

       XPAConvert -  Converting the XPA API to 2.0

SYNOPSIS

       This document describes tips for converting from xpa 1.0 (Xt-based xpa) to xpa 2.0 (socket-based xpa).

DESCRIPTION

       The following are tips for converting from xpa 1.0 (Xt-based xpa) to xpa 2.0 (socket-based xpa). The changes are straight-forward and
       almost can be done automatically (we used editor macros for most of the conversion).

       o   The existence of the cpp XPA_VERSION directive to distinguish between 1.0 (where it is not defined) and 2.0 (where it is defined).

       o   Remove the first widget argument from all send and receive server callbacks.  Also change first 2 arguments from XtPointer to void *.
	   For example:

	   #ifdef XPA_VERSION static void XPAReceiveFile(client_data, call_data, paramlist, buf, len)
		void *client_data;
		void *call_data;
		char *paramlist;
		char *buf;
		int len; #else static void XPAReceiveFile(w, client_data, call_data, paramlist, buf, len)
		Widget w;
		XtPointer client_data;
		XtPointer call_data;
		char *paramlist;
		char *buf;
		int len; #endif

       o   Server callbacks should be declared as returning int instead of void. They now should return 0 for no errors, -1 for error.

       o   The mode flags have changed when defining XPA server callbacks.  The old S flag (save buffer) is replaced by freebuf=false.	The old E
	   flag (empty buffer is OK) is no longer used (it was an artifact of the X implementation).

       o   Change NewXPACommand() to XPAcmdNew(), with the new calling sequence:

	     xpa = NewXPACommand(toplevel, NULL, prefix, NULL);

	   is changed to:

	     xpa = XPACmdNew(xclass, name);

       o   Change the AddXPACommand() subroutine name to XPACmdAdd (with the same calling sequence):

	     AddXPACommand(xpa, "file",
	       "	display a new file
		  requires: filename",
	       NULL, NULL, NULL, XPAReceiveFile, text, NULL);

	   is changed to:

	     XPACmdAdd(xpa, "file",
	       "	display a new file
		  requires: filename",
	       NULL, NULL, NULL, XPAReceiveFile, text, NULL);

       o   The XPAXtAppInput() routine should be called just before XtAppMainLoop() to add xpa fds to the Xt event loop:

	     /* add the xpas to the Xt loop */
	     XPAXtAddInput(app, NULL);

	     /* process events */
	     XtAppMainLoop(app);

       o   Change NewXPA() to XPANew() and call XPAXtAddInput() if the XtAppMainLoop routine already has been entered:

	     xpa = NewXPA(saotng->xim->toplevel, prefix, xparoot,
			  "FITS data or image filename
		  options: file type",
			  XPASendData, new, NULL,
			  XPAReceiveData, new, "SE");

	   is changed to:

	     sprintf(tbuf, "%s.%s", prefix, xparoot);
	     xpa = XPANew("SAOTNG", tbuf,
			  "FITS data or image filename
		  options: file type",
			  XPASendData, new, NULL,
			  XPAReceiveData, new, "SE");
	     XPAXtAddInput(XtWidgetToApplicationContext(saotng->xim->toplevel), xpa);

       o   Change XPAInternalReceiveCommand() to XPACmdInternalReceive() remove first argument in the calling sequence):

	     XPAInternalReceiveCommand(im->saotng->xim->toplevel,
				       im->saotng, im->saotng->commands,
				       "zoom reset", NULL, 0);

	   is changed to:

	     XPACmdInternalReceive(im->saotng, im->saotng->commands,
				   "zoom reset", NULL, 0);

       o   Change DestroyXPA to XPAFree:

	     DestroyXPA(im->dataxpa);

	   is changed to:

	     XPAFree(im->dataxpa);

SEE ALSO

       See xpa(7) for a list of XPA help pages

version 2.1.14							   June 7, 2012 						     xpaconvert(7)