xpaconvert

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