Path: utzoo!mnetor!uunet!lll-winken!lll-tis!ames!pasteur!ucbvax!ATHENA.MIT.EDU!swick
From: swick@ATHENA.MIT.EDU (Ralph R. Swick)
Newsgroups: comp.windows.x
Subject: Re: display name from within Xaw
Message-ID: <8804281342.AA01954@LYRE.MIT.EDU>
Date: 28 Apr 88 13:42:47 GMT
References: <8804272312.AA07144@velveeta>
Sender: usenet@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 31

Bob's recommendation (XDisplayString) is, of course, the correct way
to solve your problem, (see last line below), but the real bug in your
test case was incorrectly typing the resource variable.  String resources
are always passed as pointers.  The following mods make your example work:

#include <X11/Intrinsic.h>
#include <X11/StringDefs.h>

char	*display, *dspname;

static XtResource	resources[] = {
	{ "display", "Display", XtRString, sizeof(char *), (Cardinal)&display,
		  XtRString, NULL },
};

main(argc, argv)
    int argc;
    char **argv;
{
Widget top_shell = XtInitialize("top", "test", NULL, 0, &argc, argv );
if (argc != 1)
	printf("extra args\n");

XtGetApplicationResources(top_shell, (caddr_t) NULL, resources,
			  XtNumber(resources), NULL, 0);

if (display != NULL)
	printf("display=%s\n", display);
if ((dspname = XDisplayName(NULL)) != NULL)
	printf("dspname=%s\n", dspname);
printf("Display=%s\n", XDisplayString(XtDisplay(top_shell)));
}