XCircuit as a front-end GUI to ng-spice
------------------------------------------------------
XCircuit can work as an ng-spice front-end.  However,
there is the problem that ng-spice can't handle being
used interactively through a read-write pipe.  The
problem is that ngspice auto-detects whether standard
input is a tty, and if standard input is not (such as
when it is an I/O pipe), ngspice switches to batch
mode.  I submitted the patch below to the ngspice
project at SourceForge.  Hopefully it will get into
the distribution.

To test whether ngspice is patched, run XCircuit, and
type this command into the console:  "spice start".
If you get a delay followed by an error message:

   ngspice: invalid option -- p

then your version of ngspice is not patched, and you
need to apply the patch file below to the ngspice
source and recompile.

File pipemode.patch:  Put in directory ng-spice-rework-17 and
apply with the command "patch -p1 < pipemode.patch".

-------------------cut here----------------------------------------------------------
--- ng-spice-rework-17.orig/src/main.c	2006-04-05 10:52:26.060853760 -0700
+++ ng-spice-rework-17/src/main.c	2006-04-05 11:02:53.581165821 -0700
@@ -516,6 +516,7 @@
 	   "  -i, --interactive         run in interactive mode\n"
 	   "  -n, --no-spiceinit        don't load the local or user's config file\n"
 	   "  -o, --output=FILE         set the outputfile\n"
+	   "  -p, --pipe		run in I/O pipe mode\n"
 	   "  -q, --completion          activate command completion\n"
 	   "  -r, --rawfile=FILE        set the rawfile output\n"             
 	   "  -s, --server              run spice as a server process\n"
@@ -738,6 +739,7 @@
 	    {"interactive", 0, 0, 'i'},
 	    {"no-spiceinit", 0, 0, 'n'},
 	    {"output", 0, 0, 'o'},
+	    {"pipe", 0, 0, 'p'},
 	    {"completion", 0, 0, 'q'},
 	    {"rawfile", 1, 0, 'r'},
 	    {"server", 0, 0, 's'},
@@ -745,7 +747,7 @@
 	    {0, 0, 0, 0}
 	};
 
-	c = getopt_long (argc, argv, "hvbc:ihno:qr:st:",
+	c = getopt_long (argc, argv, "hvbc:ihno:pqr:st:",
 			 long_options, &option_index);
 	if (c == -1)
 	    break;