Added sim_ttisatty to support reasonable behaviour (i.e. avoid in infinite loop) in the main command input loop when EOF is detected and input is coming from a file (or a null device: /dev/null or NUL:) This may happen when a simulator is running in a background process.

scp.c

@@ -778,8 +778,9 @@ while (stat != SCPE_EXIT) {                             /* in case exit */
         cptr = (*sim_vm_read) (cbuf, CBUFSIZE, stdin);
         }
     else cptr = read_line_p ("sim> ", cbuf, CBUFSIZE, stdin);/* read with prmopt*/
-    if (cptr == NULL)                                   /* ignore EOF */
-        continue;
+    if (cptr == NULL)                                   /* EOF? */
+        if (sim_ttisatty()) continue;                   /* ignore tty EOF */
+        else break;                                     /* otherwise exit */
     if (*cptr == 0)                                     /* ignore blank */
         continue;
     sub_args (cbuf, gbuf, CBUFSIZE, argv);

sim_console.c

@@ -23,6 +23,12 @@
    used in advertising or otherwise to promote the sale, use or other dealings
    in this Software without prior written authorization from Robert M Supnik.
 
+   07-Dec-11    MP      Added sim_ttisatty to support reasonable behaviour (i.e. 
+                        avoid in infinite loop) in the main command input
+                        loop when EOF is detected and input is coming from 
+                        a file (or a null device: /dev/null or NUL:) This may
+                        happen when a simulator is running in a background 
+                        process.
    17-Apr-11    MP      Cleaned up to support running in a background/detached
                         process
    20-Jan-11    MP      Fixed support for BREAK key on Windows to account 
@@ -98,6 +104,7 @@
    sim_ttrun    -       called to put terminal into run state
    sim_ttcmd    -       called to return terminal to command state
    sim_ttclose  -       called once before the simulator exits
+   sim_ttisatty -       called to determine if running interactively
    sim_os_poll_kbd -    poll for keyboard input
    sim_os_putchar -     output character to console
 
@@ -867,6 +874,11 @@ t_stat sim_ttclose (void)
 return sim_ttcmd ();
 }
 
+t_bool sim_ttisatty (void)
+{
+return isatty (fileno (stdin));
+}
+
 t_stat sim_os_poll_kbd (void)
 {
 unsigned int status, term[2];
@@ -986,6 +998,13 @@ t_stat sim_ttclose (void)
 return SCPE_OK;
 }
 
+t_bool sim_ttisatty (void)
+{
+DWORD Mode;
+
+return (std_input) && (std_input != INVALID_HANDLE_VALUE) && GetConsoleMode (std_input, &Mode);
+}
+
 t_stat sim_os_poll_kbd (void)
 {
 int c = -1;
@@ -1063,6 +1082,11 @@ t_stat sim_ttclose (void)
 return SCPE_OK;
 }
 
+t_bool sim_ttisatty (void)
+{
+return 1;
+}
+
 t_stat sim_os_poll_kbd (void)
 {
 int c;
@@ -1259,6 +1283,11 @@ t_stat sim_ttclose (void)
 return SCPE_OK;
 }
 
+t_bool sim_ttisatty (void)
+{
+return 1;
+}
+
 t_stat sim_os_poll_kbd (void)
 {
 int c;
@@ -1355,6 +1384,11 @@ t_stat sim_ttclose (void)
 return sim_ttcmd ();
 }
 
+t_bool sim_ttisatty (void)
+{
+return isatty (0);
+}
+
 t_stat sim_os_poll_kbd (void)
 {
 int status;
@@ -1462,6 +1496,11 @@ t_stat sim_ttclose (void)
 return sim_ttcmd ();
 }
 
+t_bool sim_ttisatty(void)
+{
+return isatty (fileno (stdin));
+}
+
 t_stat sim_os_poll_kbd (void)
 {
 int status;

sim_console.h

@@ -83,6 +83,7 @@ t_stat sim_ttinit (void);
 t_stat sim_ttrun (void);
 t_stat sim_ttcmd (void);
 t_stat sim_ttclose (void);
+t_bool sim_ttisatty(void);
 t_stat sim_os_poll_kbd (void);
 t_stat sim_os_putchar (int32 out);
 int32 sim_tt_inpcvt (int32 c, uint32 mode);