Reference

xpaconvert(7)

Converting the XPA API to 2.0

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).

•

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).

•

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

•

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

•

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).

•

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

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

is changed to:

  xpa = XPACmdNew(xclass, name);
•

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

  AddXPACommand(xpa, "file",
    "\tdisplay a new file\n\t\t  requires: filename",
    NULL, NULL, NULL, XPAReceiveFile, text, NULL);

is changed to:

  XPACmdAdd(xpa, "file",
    "\tdisplay a new file\n\t\t  requires: filename",
    NULL, NULL, NULL, XPAReceiveFile, text, NULL);
•

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);
•

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\n\t\t  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\n\t\t  options: file type",
               XPASendData, new, NULL,
               XPAReceiveData, new, "SE");
  XPAXtAddInput(XtWidgetToApplicationContext(saotng->xim->toplevel), xpa);
•

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);
•

Change DestroyXPA to XPAFree:

  DestroyXPA(im->dataxpa);

is changed to:

  XPAFree(im->dataxpa);

SEE ALSO

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

History