First go at separating errors and keyboard interrupts

This is the first posting exactly as was, with known errors and
omissions.

Basic strategy is to introduce bits to errflag and to set and
reset them separately.

27 files changed, 226 insertions, 124 deletions

diff --git a/Src/Modules/zpty.c b/Src/Modules/zpty.c
index 63c79a731..7b6130c6f 100644
--- a/Src/Modules/zpty.c
+++ b/Src/Modules/zpty.c
@@ -308,7 +308,7 @@ newptycmd(char *nam, char *pname, char **args, int echo, int nblock)
 
     prog = parse_string(zjoin(args, ' ', 1), 0);
     if (!prog) {
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	scriptname = oscriptname;
 	ineval = oineval;
 	return 1;
diff --git a/Src/Modules/zutil.c b/Src/Modules/zutil.c
index 1cca0c4b8..c89495070 100644
--- a/Src/Modules/zutil.c
+++ b/Src/Modules/zutil.c
@@ -301,7 +301,8 @@ setstypat(Style s, char *pat, Patprog prog, char **vals, int eval)
 	int ef = errflag;
 
 	eprog = parse_string(zjoin(vals, ' ', 1), 0);
-	errflag = ef;
+	/* Keep any user interrupt error status */
+	errflag = ef | (errflag & ERRFLAG_INT);
 
 	if (!eprog)
 	{
@@ -394,10 +395,11 @@ evalstyle(Stypat p)
     unsetparam("reply");
     execode(p->eval, 1, 0, "style");
     if (errflag) {
-	errflag = ef;
+	/* Keep any user interrupt error status */
+	errflag = ef | (errflag & ERRFLAG_INT);
 	return NULL;
     }
-    errflag = ef;
+    errflag = ef | (errflag & ERRFLAG_INT);
 
     queue_signals();
     if ((ret = getaparam("reply")))
diff --git a/Src/Zle/compcore.c b/Src/Zle/compcore.c
index 35d410cc6..b0c6e06f8 100644
--- a/Src/Zle/compcore.c
+++ b/Src/Zle/compcore.c
@@ -1671,7 +1671,7 @@ set_comp_sep(void)
     noaliases = ona;
     strinend();
     inpop();
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     noerrs = ne;
     lexrestore();
     wb = owb;
diff --git a/Src/Zle/compctl.c b/Src/Zle/compctl.c
index 0b7a32445..d15c2d1b0 100644
--- a/Src/Zle/compctl.c
+++ b/Src/Zle/compctl.c
@@ -1879,7 +1879,7 @@ ccmakehookfn(UNUSED(Hookdef dummy), struct ccmakedat *dat)
 	if (!m || !(m = m->next))
 	    break;
 
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
     }
     redup(osi, 0);
     dat->lst = 1;
@@ -2121,7 +2121,7 @@ getreal(char *str)
     if (!errflag && nonempty(l) &&
 	((char *) peekfirst(l)) && ((char *) peekfirst(l))[0])
 	return dupstring(peekfirst(l));
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
 
     return dupstring(str);
 }
@@ -2599,7 +2599,7 @@ makecomplistlist(Compctl cc, char *s, int incmd, int compadd)
 	makecomplistflags(cc, s, incmd, compadd);
 
     /* Reset some information variables for the next try. */
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     offs = oloffs;
     wb = owb;
     we = owe;
@@ -2847,7 +2847,7 @@ sep_comp_string(char *ss, char *s, int noffs)
     noaliases = ona;
     strinend();
     inpop();
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     noerrs = ne;
     lexrestore();
     wb = owb;
@@ -3725,7 +3725,7 @@ makecomplistflags(Compctl cc, char *s, int incmd, int compadd)
 	noaliases = ona;
 	strinend();
 	inpop();
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	lexrestore();
 	/* Fine, now do full expansion. */
 	prefork(foo, 0);
diff --git a/Src/Zle/compresult.c b/Src/Zle/compresult.c
index fcceb670c..93438a053 100644
--- a/Src/Zle/compresult.c
+++ b/Src/Zle/compresult.c
@@ -1092,7 +1092,7 @@ do_single(Cmatch m)
 			noerrs = 1;
 			parsestr(p);
 			singsub(&p);
-			errflag = 0;
+			errflag &= ~ERRFLAG_ERROR;
 			noerrs = ne;
 		    }
 		} else {
diff --git a/Src/Zle/textobjects.c b/Src/Zle/textobjects.c
index 85d014b27..37d2c0ad9 100644
--- a/Src/Zle/textobjects.c
+++ b/Src/Zle/textobjects.c
@@ -275,7 +275,7 @@ selectargument(UNUSED(char **args))
     noaliases = ona;
     strinend();
     inpop();
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     noerrs = ne;
     lexrestore();
     zlemetacs = ocs;
diff --git a/Src/Zle/zle_hist.c b/Src/Zle/zle_hist.c
index 9f65994dc..88623bb3c 100644
--- a/Src/Zle/zle_hist.c
+++ b/Src/Zle/zle_hist.c
@@ -853,8 +853,10 @@ pushlineoredit(char **args)
 	free(zhline);
     }
     ret = pushline(args);
-    if (!isfirstln)
-	errflag = done = 1;
+    if (!isfirstln) {
+	errflag |= ERRFLAG_ERROR;
+	done = 1;
+    }
     clearlist = 1;
     return ret;
 }
diff --git a/Src/Zle/zle_main.c b/Src/Zle/zle_main.c
index caa052b13..616f3543c 100644
--- a/Src/Zle/zle_main.c
+++ b/Src/Zle/zle_main.c
@@ -744,7 +744,7 @@ raw_getbyte(long do_keytmout, char *cptr)
 			}
 			if (errflag) {
 			    /* No sensible way of handling errors here */
-			    errflag = 0;
+			    errflag &= ~ERRFLAG_ERROR;
 			    /*
 			     * Paranoia: don't run the hooks again this
 			     * time.
@@ -882,7 +882,7 @@ getbyte(long do_keytmout, int *timeout)
 		die = 0;
 		if (!errflag && !retflag && !breaks && !exit_pending)
 		    continue;
-		errflag = 0;
+		errflag &= ~ERRFLAG_ERROR;
 		breaks = obreaks;
 		errno = old_errno;
 		return lastchar = EOF;
@@ -1075,7 +1075,7 @@ zlecore(void)
 		DECCS();
 	    handleundo();
 	} else {
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
 	    break;
 	}
 #ifdef HAVE_POLL
@@ -1233,6 +1233,10 @@ zleread(char **lp, char **rp, int flags, int context, char *init, char *finish)
 
     zleactive = 1;
     resetneeded = 1;
+    /*
+     * Start of the main zle read.
+     * Fully reset error conditions, including error interrupt.
+     */
     errflag = retflag = 0;
     lastcol = -1;
     initmodifier(&zmod);
@@ -1658,7 +1662,7 @@ bin_vared(char *name, char **args, Options ops, UNUSED(int func))
     }
     if (!t || errflag) {
 	/* error in editing */
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	breaks = obreaks;
 	if (t)
 	    zsfree(t);
@@ -1778,7 +1782,7 @@ recursiveedit(UNUSED(char **args))
     zrefresh();
     zlecore();
 
-    locerror = errflag;
+    locerror = errflag ? 1 : 0;
     errflag = done = eofsent = 0;
 
     return locerror;
diff --git a/Src/Zle/zle_misc.c b/Src/Zle/zle_misc.c
index d432acf7b..23286fc20 100644
--- a/Src/Zle/zle_misc.c
+++ b/Src/Zle/zle_misc.c
@@ -1041,7 +1041,7 @@ copyprevshellword(UNUSED(char **args))
 int
 sendbreak(UNUSED(char **args))
 {
-    errflag = 1;
+    errflag |= ERRFLAG_ERROR;
     return 1;
 }
 
diff --git a/Src/Zle/zle_tricky.c b/Src/Zle/zle_tricky.c
index b15d91c8e..864f804b7 100644
--- a/Src/Zle/zle_tricky.c
+++ b/Src/Zle/zle_tricky.c
@@ -829,7 +829,7 @@ docomplete(int lst)
 	    if (olst == COMP_EXPAND_COMPLETE &&
 		!strcmp(ol, zlemetaline)) {
 		zlemetacs = ocs;
-		errflag = 0;
+		errflag &= ~ERRFLAG_ERROR;
 
 		if (!compfunc) {
 		    char *p;
@@ -877,6 +877,19 @@ docomplete(int lst)
 
     active = 0;
     makecommaspecial(0);
+
+    /*
+     * As a special case, we reset user interrupts here.
+     * That's because completion is an intensive piece of
+     * computation that the user might want to interrupt separately
+     * from anything else going on.  If they do, they probably
+     * want to keep the line edit buffer intact.
+     *
+     * There's a race here that the user might hit ^C just
+     * after completion exited anyway, but that's inevitable.
+     */
+    errflag &= ~ERRFLAG_INT;
+
     return dat[1];
 }
 
@@ -1394,7 +1407,8 @@ get_comp_string(void)
     }
     strinend();
     inpop();
-    errflag = lexflags = 0;
+    lexflags = 0;
+    errflag &= ~ERRFLAG_ERROR;
     if (parbegin != -1) {
 	/* We are in command or process substitution if we are not in
 	 * a $((...)). */
@@ -2917,7 +2931,7 @@ getcurcmd(void)
     popheap();
     strinend();
     inpop();
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     unmetafy_line();
     lexrestore();
 
diff --git a/Src/Zle/zle_utils.c b/Src/Zle/zle_utils.c
index 08a32c30e..de91182b5 100644
--- a/Src/Zle/zle_utils.c
+++ b/Src/Zle/zle_utils.c
@@ -1715,7 +1715,8 @@ zlecallhook(char *name, char *arg)
     execzlefunc(thingy, args, 1);
     unrefthingy(thingy);
 
-    errflag = saverrflag;
+    /* Retain any user interrupt error status */
+    errflag = saverrflag | (errflag & ERRFLAG_INT);
     retflag = savretflag;
 }
 
diff --git a/Src/builtin.c b/Src/builtin.c
index c2af51f2e..ad3a1925f 100644
--- a/Src/builtin.c
+++ b/Src/builtin.c
@@ -422,7 +422,7 @@ execbuiltin(LinkList args, Builtin bn)
 	argc -= argv - argarr;
 
 	if (errflag) {
-	    errflag = 0;
+	    errflag &= ~ERRFLAG_ERROR;
 	    return 1;
 	}
 
@@ -3136,7 +3136,7 @@ bin_unset(char *name, char **argv, Options ops, int func)
 		    }
 		}
 		returnval = errflag;
-		errflag = 0;
+		errflag &= ~ERRFLAG_ERROR;
 	    } else {
 		zerrnam(name, "%s: invalid element for unset", s);
 		returnval = 1;
@@ -4242,7 +4242,7 @@ bin_print(char *name, char **args, Options ops, int func)
 		if (*argp) {
 		    width = (int)mathevali(*argp++);
 		    if (errflag) {
-			errflag = 0;
+			errflag &= ~ERRFLAG_ERROR;
 			ret = 1;
 		    }
 		}
@@ -4272,7 +4272,7 @@ bin_print(char *name, char **args, Options ops, int func)
 		    if (*argp) {
 			prec = (int)mathevali(*argp++);
 			if (errflag) {
-			    errflag = 0;
+			    errflag &= ~ERRFLAG_ERROR;
 			    ret = 1;
 			}
 		    }
@@ -4452,7 +4452,7 @@ bin_print(char *name, char **args, Options ops, int func)
 			zlongval = (curarg) ? mathevali(curarg) : 0;
 			if (errflag) {
 			    zlongval = 0;
-			    errflag = 0;
+			    errflag &= ~ERRFLAG_ERROR;
 			    ret = 1;
 			}
 			print_val(zlongval)
@@ -4481,7 +4481,7 @@ bin_print(char *name, char **args, Options ops, int func)
 			} else doubleval = 0;
 			if (errflag) {
 			    doubleval = 0;
-			    errflag = 0;
+			    errflag &= ~ERRFLAG_ERROR;
 			    ret = 1;
 			}
 			print_val(doubleval)
@@ -4494,7 +4494,7 @@ bin_print(char *name, char **args, Options ops, int func)
 			zulongval = (curarg) ? mathevali(curarg) : 0;
 			if (errflag) {
 			    zulongval = 0;
-			    errflag = 0;
+			    errflag &= ~ERRFLAG_ERROR;
 			    ret = 1;
 			}
 			print_val(zulongval)
@@ -4871,7 +4871,7 @@ zexit(int val, int from_where)
     in_exit = -1;
     /*
      * We want to do all remaining processing regardless of preceding
-     * errors.
+     * errors, even user interrupts.
      */
     errflag = 0;
 
@@ -5074,7 +5074,7 @@ eval(char **argv)
     if (fpushed)
 	funcstack = funcstack->prev;
 
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     scriptname = oscriptname;
     ineval = oineval;
 
@@ -6101,7 +6101,7 @@ bin_test(char *name, char **argv, UNUSED(Options ops), int func)
     condlex = zshlex;
 
     if (errflag) {
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	lexrestore();
 	return 1;
     }
@@ -6278,7 +6278,7 @@ bin_let(UNUSED(char *name), char **argv, UNUSED(Options ops), UNUSED(int func))
     while (*argv)
 	val = matheval(*argv++);
     /* Errors in math evaluation in let are non-fatal. */
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     /* should test for fabs(val.u.d) < epsilon? */
     return (val.type == MN_INTEGER) ? val.u.l == 0 : val.u.d == 0.0;
 }
diff --git a/Src/exec.c b/Src/exec.c
index a5f877191..c18f3cd1e 100644
--- a/Src/exec.c
+++ b/Src/exec.c
@@ -59,7 +59,7 @@ mod_export int noerrs;
 /**/
 int nohistsave;
 
-/* error/break flag */
+/* error flag: bits from enum errflag_bits */
 
 /**/
 mod_export int errflag;
@@ -1601,7 +1601,8 @@ execpline(Estate state, wordcode slcode, int how, int last1)
 			    (killpg(jobtab[list_pipe_job].gleader, 0) == -1 ? 2 : 1);
 			list_pipe_pid = pid;
 			list_pipe_start = bgtime;
-			nowait = errflag = 1;
+			nowait = 1;
+			errflag |= ERRFLAG_ERROR;
 			breaks = loops;
 			close(synch[1]);
 			read_loop(synch[0], &dummy, 1);
@@ -1634,7 +1635,10 @@ execpline(Estate state, wordcode slcode, int how, int last1)
 			list_pipe_child = 1;
 			opts[INTERACTIVE] = 0;
 			if (errbrk_saved) {
-			    errflag = prev_errflag;
+			    /*
+			     * Keep any user interrupt bit in errflag.
+			     */
+			    errflag = prev_errflag | (errflag & ERRFLAG_INT);
 			    breaks = prev_breaks;
 			}
 			break;
@@ -1719,12 +1723,14 @@ execpline2(Estate state, wordcode pcode,
 
 	    if (pipe(synch) < 0) {
 		zerr("pipe failed: %e", errno);
-		lastval = errflag = 1;
+		lastval = 1;
+		errflag |= ERRFLAG_ERROR;
 		return;
 	    } else if ((pid = zfork(&bgtime)) == -1) {
 		close(synch[0]);
 		close(synch[1]);
-		lastval = errflag = 1;
+		lastval = 1;
+		errflag |= ERRFLAG_ERROR;
 		return;
 	    } else if (pid) {
 		char dummy, *text;
@@ -2560,7 +2566,8 @@ execcmd(Estate state, int input, int output, int how, int last1)
 		while (next && *next == '-' && strlen(next) >= 2) {
 		    if (!firstnode(args)) {
 			zerr("exec requires a command to execute");
-			errflag = lastval = 1;
+			lastval = 1;
+			errflag |= ERRFLAG_ERROR;
 			goto done;
 		    }
 		    uremnode(args, firstnode(args));
@@ -2577,12 +2584,14 @@ execcmd(Estate state, int input, int output, int how, int last1)
 			    } else {
 				if (!firstnode(args)) {
 				    zerr("exec requires a command to execute");
-				    errflag = lastval = 1;
+				    lastval = 1;
+				    errflag |= ERRFLAG_ERROR;
 				    goto done;
 				}
 				if (!nextnode(firstnode(args))) {
 				    zerr("exec flag -a requires a parameter");
-				    errflag = lastval = 1;
+				    lastval = 1;
+				    errflag |= ERRFLAG_ERROR;
 				    goto done;
 				}
 				exec_argv0 = (char *)
@@ -2598,7 +2607,8 @@ execcmd(Estate state, int input, int output, int how, int last1)
 			    break;
 			default:
 			    zerr("unknown exec flag -%c", *cmdopt);
-			    errflag = lastval = 1;
+			    lastval = 1;
+			    errflag |= ERRFLAG_ERROR;
 			    return;
 			}
 		    }
@@ -2661,7 +2671,8 @@ execcmd(Estate state, int input, int output, int how, int last1)
 		    } else if (!nullcmd || !*nullcmd || opts[CSHNULLCMD] ||
 			       (cflags & BINF_PREFIX)) {
 			zerr("redirection with no command");
-			errflag = lastval = 1;
+			lastval = 1;
+			errflag |= ERRFLAG_ERROR;
 			return;
 		    } else if (!nullcmd || !*nullcmd || opts[SHNULLCMD]) {
 			if (!args)
@@ -2691,7 +2702,7 @@ execcmd(Estate state, int input, int output, int how, int last1)
 		    if (varspc)
 			addvars(state, varspc, 0);
 		    if (errflag)
-			lastval = errflag;
+			lastval = errflag ? 1 : 0;
 		    else
 			lastval = cmdoutval;
 		    if (isset(XTRACE)) {
@@ -2795,7 +2806,7 @@ execcmd(Estate state, int input, int output, int how, int last1)
 	    }
 	}
 	if (!nextnode(firstnode(args)))
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
     }
 
     if (type == WC_FUNCDEF) {
@@ -2940,7 +2951,8 @@ execcmd(Estate state, int input, int output, int how, int last1)
 	} else if ((pid = zfork(&bgtime)) == -1) {
 	    close(synch[0]);
 	    close(synch[1]);
-	    lastval = errflag = 1;
+	    lastval = 1;
+	    errflag |= ERRFLAG_ERROR;
 	    goto fatal;
 	}
 	if (pid) {
@@ -3529,7 +3541,7 @@ execcmd(Estate state, int input, int output, int how, int last1)
 		else
 		    exit(1);
 	    }
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
 	}
     }
     if (newxtrerr) {
@@ -3759,8 +3771,10 @@ gethere(char **strp, int typ)
 
 	parsestr(buf);
 
-	if (!errflag)
-	    errflag = ef;
+	if (!errflag) {
+	    /* Retain any user interrupt error */
+	    errflag = ef | (errflag & ERRFLAG_INT);
+	}
     }
     s = dupstring(buf);
     zfree(buf, bsiz);
@@ -3854,7 +3868,7 @@ getoutput(char *cmd, int qt)
 	return readoutput(stream, qt);
     }
     if (mpipe(pipes) < 0) {
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	cmdoutpid = 0;
 	return NULL;
     }
@@ -3864,7 +3878,7 @@ getoutput(char *cmd, int qt)
 	/* fork error */
 	zclose(pipes[0]);
 	zclose(pipes[1]);
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	cmdoutpid = 0;
 	child_unblock();
 	return NULL;
@@ -4274,7 +4288,7 @@ execcond(Estate state, UNUSED(int do_exec))
      * into a shell error.
      */
     if (stat == 2)
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
     cmdpop();
     if (isset(XTRACE)) {
 	fprintf(xtrerr, " ]]\n");
@@ -4314,7 +4328,7 @@ execarith(Estate state, UNUSED(int do_exec))
 	fflush(xtrerr);
     }
     if (errflag) {
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	return 2;
     }
     /* should test for fabs(val.u.d) < epsilon? */
@@ -4932,7 +4946,7 @@ doshfunc(Shfunc shfunc, LinkList doshargs, int noreturnval)
 						(name = fname)))) {
 	    zwarn("%s: function not defined by file", name);
 	    if (noreturnval)
-		errflag = 1;
+		errflag |= ERRFLAG_ERROR;
 	    else
 		lastval = 1;
 	    goto doneshfunc;
diff --git a/Src/glob.c b/Src/glob.c
index ca7bc4410..f5ac47a12 100644
--- a/Src/glob.c
+++ b/Src/glob.c
@@ -682,7 +682,7 @@ parsecomplist(char *instr)
 	/* Now get the next path component if there is one. */
 	l1 = (Complist) zhalloc(sizeof *l1);
 	if ((l1->next = parsecomplist(instr)) == NULL) {
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
 	    return NULL;
 	}
 	l1->pat = patcompile(NULL, compflags | PAT_ANY, NULL);
@@ -728,7 +728,7 @@ parsecomplist(char *instr)
 	    return (ef && !l1->next) ? NULL : l1;
 	}
     }
-    errflag = 1;
+    errflag |= ERRFLAG_ERROR;
     return NULL;
 }
 
@@ -1790,7 +1790,7 @@ zglob(LinkList list, LinkNode np, int nountok)
 	    insertlinknode(list, node, ostr);
 	    return;
 	}
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	zerr("bad pattern: %s", ostr);
 	return;
     }
@@ -1873,7 +1873,8 @@ zglob(LinkList list, LinkNode np, int nountok)
 				tmpptr->sortstrs[iexec] = tmpptr->name;
 			}
 
-			errflag = ef;
+			/* Retain any user interrupt error status */
+			errflag = ef | (errflag & ERRFLAG_INT);
 			lastval = lv;
 		    } else {
 			/* Failed, let's be safe */
@@ -3733,7 +3734,8 @@ qualsheval(char *name, UNUSED(struct stat *buf), UNUSED(off_t days), char *str)
 	execode(prog, 1, 0, "globqual");
 
 	ret = lastval;
-	errflag = ef;
+	/* Retain any user interrupt error status */
+	errflag = ef | (errflag & ERRFLAG_INT);
 	lastval = lv;
 
 	if (!(inserts = getaparam("reply")) &&
diff --git a/Src/hist.c b/Src/hist.c
index 7fe843a4a..a0061707c 100644
--- a/Src/hist.c
+++ b/Src/hist.c
@@ -287,7 +287,8 @@ ihgetc(void)
 	c = histsubchar(c);
 	if (c < 0) {
 	    /* bad expansion */
-	    errflag = lexstop = 1;
+	    lexstop = 1;
+	    errflag |= ERRFLAG_ERROR;
 	    return ' ';
 	}
     }
@@ -721,7 +722,7 @@ histsubchar(int c)
 		    noerrs = 1;
 		    parse_subst_string(sline);
 		    noerrs = one;
-		    errflag = oef;
+		    errflag = oef | (errflag & ERRFLAG_INT);
 		    remnulargs(sline);
 		    untokenize(sline);
 		}
@@ -880,7 +881,8 @@ hbegin(int dohist)
     char *hf;
 
     isfirstln = isfirstch = 1;
-    errflag = histdone = 0;
+    errflag &= ~ERRFLAG_ERROR;
+    histdone = 0;
     if (!dohist)
 	stophist = 2;
     else if (dohist != 2)
@@ -3182,7 +3184,7 @@ bufferwords(LinkList list, char *buf, int *index, int flags)
     noaliases = ona;
     strinend();
     inpop();
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     nocomments = onc;
     noerrs = ne;
     lexrestore();
diff --git a/Src/init.c b/Src/init.c
index 655166135..3cbd4e522 100644
--- a/Src/init.c
+++ b/Src/init.c
@@ -123,6 +123,11 @@ loop(int toplevel, int justonce)
 		    hbegin(1);
 		else
 		    stophist = hstop;
+		/*
+		 * Reset all errors, including user interupts.
+		 * This is what allows ^C in an interactive shell
+		 * to return us to the command line.
+		 */
 		errflag = 0;
 	    }
 	}
@@ -178,7 +183,15 @@ loop(int toplevel, int justonce)
 
 		/* The only permanent storage is from getpermtext() */
 		zsfree(cmdstr);
-		errflag = 0;
+		/*
+		 * Note this does *not* remove a user interrupt error
+		 * condition, even though we're at the top level loop:
+		 * that would be inconsistent with the case where
+		 * we didn't execute a preexec function.  This is
+		 * an implementation detail that an interrupting user
+		 * does't care about.
+		 */
+		errflag &= ~ERRFLAG_ERROR;
 	    }
 	    if (stopmsg)	/* unset 'you have stopped jobs' flag */
 		stopmsg--;
@@ -689,7 +702,7 @@ init_term(void)
     {
 	if (isset(INTERACTIVE))
 	    zerr("can't find terminal definition for %s", term);
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	termflags |= TERM_BAD;
 	return 0;
     } else {
@@ -1336,7 +1349,7 @@ source(char *s)
 
     if (prog) {
 	pushheap();
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	execode(prog, 1, 0, "filecode");
 	popheap();
 	if (errflag)
@@ -1379,7 +1392,7 @@ source(char *s)
     lineno = oldlineno;              /* our current lineno                   */
     loops = oloops;                  /* the # of nested loops we are in      */
     dosetopt(SHINSTDIN, oldshst, 1, opts); /* SHINSTDIN option               */
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     if (!exit_pending)
 	retflag = 0;
     scriptname = old_scriptname;
diff --git a/Src/input.c b/Src/input.c
index 4ac7e6ec8..9552331a9 100644
--- a/Src/input.c
+++ b/Src/input.c
@@ -291,7 +291,8 @@ inputline(void)
     }
     if (errflag) {
 	free(ingetcline);
-	return lexstop = errflag = 1;
+	errflag |= ERRFLAG_ERROR;
+	return lexstop = 1;
     }
     if (isset(VERBOSE)) {
 	/* Output the whole line read so far. */
diff --git a/Src/jobs.c b/Src/jobs.c
index 6663a40a6..6e47e5e54 100644
--- a/Src/jobs.c
+++ b/Src/jobs.c
@@ -509,7 +509,7 @@ update_job(Job jn)
 			prev_errflag = errflag;
 		    }
 		    breaks = loops;
-		    errflag = 1;
+		    errflag |= ERRFLAG_ERROR;
 		    inerrflush();
 		}
 	    } else {
@@ -526,7 +526,7 @@ update_job(Job jn)
 	    prev_errflag = errflag;
 	}
 	breaks = loops;
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	inerrflush();
     }
     if (somestopped && jn->stat & STAT_SUPERJOB)
@@ -581,7 +581,7 @@ update_job(Job jn)
 		    breaks = loops;
 	    } else {
 		breaks = loops;
-		errflag = 1;
+		errflag |= ERRFLAG_ERROR;
 	    }
 	    check_cursh_sig(sig);
 	}
@@ -1444,12 +1444,7 @@ zwaitjob(int job, int wait_cmd)
 		restore_queue_signals(q);
 		return 128 + last_signal;
 	    }
-	    /* Commenting this out makes ^C-ing a job started by a function
-	       stop the whole function again.  But I guess it will stop
-	       something else from working properly, we have to find out
-	       what this might be.  --oberon
-
-	    errflag = 0; */
+	    errflag &= ~ERRFLAG_ERROR;
 	    if (subsh) {
 		killjb(jn, SIGCONT);
 		jn->stat &= ~STAT_STOPPED;
diff --git a/Src/lex.c b/Src/lex.c
index 1a854f52b..68a892a72 100644
--- a/Src/lex.c
+++ b/Src/lex.c
@@ -385,7 +385,7 @@ lexrestore(void)
     ecnfunc = ln->ecnfunc;
     hlinesz = ln->hlinesz;
     toklineno = ln->toklineno;
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     free(ln);
 
     unqueue_signals();
@@ -1725,7 +1725,8 @@ parse_subst_string(char *s)
     inpop();
     DPUTS(cmdsp, "BUG: parse_subst_string: cmdstack not empty.");
     lexrestore();
-    errflag = err;
+    /* Keep any interrupt error status */
+    errflag = err | (errflag & ERRFLAG_INT);
     if (ctok == LEXERR) {
 	untokenize(s);
 	return 1;
diff --git a/Src/loop.c b/Src/loop.c
index 82d2fe31a..69805ea9e 100644
--- a/Src/loop.c
+++ b/Src/loop.c
@@ -259,7 +259,8 @@ execselect(Estate state, UNUSED(int do_exec))
 				   0, ZLCON_SELECT);
 		    if (errflag)
 			str = NULL;
-		    errflag = oef;
+		    /* Keep any user interrupt error status */
+		    errflag = oef | (errflag & ERRFLAG_INT);
 	    	} else {
 		    str = promptexpand(prompt3, 0, NULL, NULL, NULL);
 		    zputs(str, stderr);
@@ -671,7 +672,7 @@ exectry(Estate state, int do_exec)
     /* The always clause. */
     save_try_errflag = try_errflag;
     try_errflag = (zlong)errflag;
-    errflag = 0;
+    errflag &= ~ERRFLAG_ERROR;
     save_retflag = retflag;
     retflag = 0;
     save_breaks = breaks;
@@ -682,7 +683,10 @@ exectry(Estate state, int do_exec)
     state->pc = always;
     execlist(state, 1, do_exec);
 
-    errflag = try_errflag ? 1 : 0;
+    if (try_errflag)
+	errflag |= ERRFLAG_ERROR;
+    else
+	errflag &= ~ERRFLAG_ERROR;
     try_errflag = save_try_errflag;
     if (!retflag)
 	retflag = save_retflag;
diff --git a/Src/params.c b/Src/params.c
index 61edc5d08..bdace7928 100644
--- a/Src/params.c
+++ b/Src/params.c
@@ -2654,7 +2654,7 @@ assignsparam(char *s, char *val, int flags)
     if (!isident(s)) {
 	zerr("not an identifier: %s", s);
 	zsfree(val);
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	return NULL;
     }
     queue_signals();
@@ -2783,7 +2783,7 @@ assignaparam(char *s, char **val, int flags)
     if (!isident(s)) {
 	zerr("not an identifier: %s", s);
 	freearray(val);
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	return NULL;
     }
     queue_signals();
@@ -2799,7 +2799,7 @@ assignaparam(char *s, char **val, int flags)
 	    zerr("%s: attempt to set slice of associative array",
 		 v->pm->node.nam);
 	    freearray(val);
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
 	    return NULL;
 	}
 	v = NULL;
@@ -2870,13 +2870,13 @@ sethparam(char *s, char **val)
     if (!isident(s)) {
 	zerr("not an identifier: %s", s);
 	freearray(val);
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	return NULL;
     }
     if (strchr(s, '[')) {
 	freearray(val);
 	zerr("nested associative arrays not yet supported");
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	return NULL;
     }
     if (unset(EXECOPT))
@@ -2916,7 +2916,7 @@ setnparam(char *s, mnumber val)
 
     if (!isident(s)) {
 	zerr("not an identifier: %s", s);
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 	return NULL;
     }
     if (unset(EXECOPT))
diff --git a/Src/parse.c b/Src/parse.c
index 4ceeb4eaf..c1709e03a 100644
--- a/Src/parse.c
+++ b/Src/parse.c
@@ -71,13 +71,14 @@ struct heredocs *hdocs;
 
 #define YYERROR(O)  { tok = LEXERR; ecused = (O); return 0; }
 #define YYERRORV(O) { tok = LEXERR; ecused = (O); return; }
-#define COND_ERROR(X,Y) do { \
-  zwarn(X,Y); \
-  herrflush(); \
-  if (noerrs != 2) \
-    errflag = 1; \
-  YYERROR(ecused) \
-} while(0)
+#define COND_ERROR(X,Y) \
+    do {					\
+	zwarn(X,Y);				\
+	herrflush();				\
+	if (noerrs != 2)			\
+	    errflag |= ERRFLAG_ERROR;		\
+	YYERROR(ecused)				\
+	    } while(0)
 
 
 /* 
@@ -506,7 +507,7 @@ par_event(void)
 	yyerror(1);
 	herrflush();
 	if (noerrs != 2)
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
 	ecused--;
 	return 0;
     } else {
@@ -2339,7 +2340,7 @@ yyerror(int noerr)
 	    zwarn("parse error");
     }
     if (!noerr && noerrs != 2)
-	errflag = 1;
+	errflag |= ERRFLAG_ERROR;
 }
 
 /*
@@ -3031,7 +3032,7 @@ build_dump(char *nam, char *dump, char **files, int ali, int map, int flags)
 	file = metafy(file, flen, META_REALLOC);
 
 	if (!(prog = parse_string(file, 1)) || errflag) {
-	    errflag = 0;
+	    errflag &= ~ERRFLAG_ERROR;
 	    close(dfd);
 	    zfree(file, flen);
 	    zwarnnam(nam, "can't read file: %s", *files);
@@ -3141,7 +3142,7 @@ build_cur_dump(char *nam, char *dump, char **names, int match, int map,
 	    for (hn = shfunctab->nodes[i]; hn; hn = hn->next)
 		if (cur_add_func(nam, (Shfunc) hn, lnames, progs,
 				 &hlen, &tlen, what)) {
-		    errflag = 0;
+		    errflag &= ~ERRFLAG_ERROR;
 		    close(dfd);
 		    unlink(dump);
 		    return 1;
@@ -3166,7 +3167,7 @@ build_cur_dump(char *nam, char *dump, char **names, int match, int map,
 			pattry(pprog, hn->nam) &&
 			cur_add_func(nam, (Shfunc) hn, lnames, progs,
 				     &hlen, &tlen, what)) {
-			errflag = 0;
+			errflag &= ~ERRFLAG_ERROR;
 			close(dfd);
 			unlink(dump);
 			return 1;
@@ -3177,13 +3178,13 @@ build_cur_dump(char *nam, char *dump, char **names, int match, int map,
 	    if (errflag ||
 		!(shf = (Shfunc) shfunctab->getnode(shfunctab, *names))) {
 		zwarnnam(nam, "unknown function: %s", *names);
-		errflag = 0;
+		errflag &= ~ERRFLAG_ERROR;
 		close(dfd);
 		unlink(dump);
 		return 1;
 	    }
 	    if (cur_add_func(nam, shf, lnames, progs, &hlen, &tlen, what)) {
-		errflag = 0;
+		errflag &= ~ERRFLAG_ERROR;
 		close(dfd);
 		unlink(dump);
 		return 1;
@@ -3192,7 +3193,7 @@ build_cur_dump(char *nam, char *dump, char **names, int match, int map,
     }
     if (empty(progs)) {
 	zwarnnam(nam, "no functions");
-	errflag = 0;
+	errflag &= ~ERRFLAG_ERROR;
 	close(dfd);
 	unlink(dump);
 	return 1;
diff --git a/Src/prompt.c b/Src/prompt.c
index 0cc9ef917..3552575f3 100644
--- a/Src/prompt.c
+++ b/Src/prompt.c
@@ -192,8 +192,11 @@ promptexpand(char *s, int ns, char *rs, char *Rs, unsigned int *txtchangep)
 	if (*s == Nularg && s[1] == '\0')
 	    *s = '\0';
 
-	/* Ignore errors and status change in prompt substitution */
-	errflag = olderr;
+	/*
+	 * Ignore errors and status change in prompt substitution.
+	 * However, keep any user interrupt error that occurred.
+	 */
+	errflag = olderr | (errflag & ERRFLAG_INT);
 	lastval = oldval;
     }
 
diff --git a/Src/signals.c b/Src/signals.c
index e72850516..899f1217b 100644
--- a/Src/signals.c
+++ b/Src/signals.c
@@ -619,7 +619,7 @@ zhandler(int sig)
 		zexit(SIGINT, 1);
             if (list_pipe || chline || simple_pline) {
                 breaks = loops;
-                errflag = 1;
+                errflag |= ERRFLAG_INT;
 		inerrflush();
 		check_cursh_sig(SIGINT);
             }
@@ -640,6 +640,11 @@ zhandler(int sig)
 	    if (idle >= 0 && idle < tmout)
 		alarm(tmout - idle);
 	    else {
+		/*
+		 * We want to exit now.
+		 * Cancel all errors, including a user interrupt
+		 * which is now redundant.
+		 */
 		errflag = noerrs = 0;
 		zwarn("timeout");
 		stopmsg = 1;
@@ -1267,7 +1272,18 @@ dotrapargs(int sig, int *sigtr, void *sigfn)
 	!(isfunc && new_trap_return == 0)) {
 	if (isfunc) {
 	    breaks = loops;
-	    errflag = 1;
+	    /*
+	     * For SIGINT we behave the same as the default behaviour
+	     * i.e. we set the error bit indicating an interrupt.
+	     * We do this with SIGQUIT, too, even though we don't
+	     * handle SIGQUIT by default.  That's to try to make
+	     * it behave a bit more like its normal behaviour when
+	     * the trap handler has told us that's what it wants.
+	     */
+	    if (sig == SIGINT || sig == SIGQUIT)
+		errflag |= ERRFLAG_INT;
+	    else
+		errflag |= ERRFLAG_ERROR;
 	}
 	lastval = new_trap_return;
 	/* return triggered */
@@ -1282,8 +1298,12 @@ dotrapargs(int sig, int *sigtr, void *sigfn)
 	     */
 	    lastval = olastval;
 	}
-	if (try_tryflag)
-	    errflag = traperr;
+	if (try_tryflag) {
+	    if (traperr)
+		errflag |= ERRFLAG_ERROR;
+	    else
+		errflag &= ~ERRFLAG_ERROR;
+	}
 	breaks += obreaks;
 	/* return not triggered: restore old flag */
 	retflag = oretflag;
diff --git a/Src/subst.c b/Src/subst.c
index 61aa1c136..43932c256 100644
--- a/Src/subst.c
+++ b/Src/subst.c
@@ -2822,7 +2822,8 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 		haserr = parse_subst_string(s);
 		noerrs = one;
 		if (!quoteerr) {
-		    errflag = oef;
+		    /* Retain user interrupt error status */
+		    errflag = oef | (errflag & ERRFLAG_INT);
 		    if (haserr)
 			shtokenize(s);
 		} else if (haserr || errflag) {
@@ -3249,8 +3250,10 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 		haserr = 1;
 	}
 	noerrs = one;
-	if (!quoteerr)
-	    errflag = oef;
+	if (!quoteerr) {
+	    /* Retain user interrupt error status */
+	    errflag = oef | (errflag & ERRFLAG_INT);
+	}
 	if (haserr || errflag)
 	    return NULL;
     }
@@ -3483,8 +3486,10 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 		    untokenize(*ap);
 		}
 		noerrs = one;
-		if (!quoteerr)
-		    errflag = oef;
+		if (!quoteerr) {
+		    /* Retain any user interrupt error status */
+		    errflag = oef | (errflag & ERRFLAG_INT);
+		}
 		else if (haserr || errflag) {
 		    zerr("parse error in parameter value");
 		    return NULL;
@@ -3516,8 +3521,10 @@ paramsubst(LinkList l, LinkNode n, char **str, int qt, int pf_flags)
 		    noerrs = 1;
 		haserr = parse_subst_string(val);
 		noerrs = one;
-		if (!quoteerr)
-		    errflag = oef;
+		if (!quoteerr) {
+		    /* Retain any user interrupt error status */
+		    errflag = oef | (errflag & ERRFLAG_INT);
+		}
 		else if (haserr || errflag) {
 		    zerr("parse error in parameter value");
 		    return NULL;
@@ -4086,7 +4093,8 @@ modify(char **str, char **ptr)
 			    noerrs = 1;
 			    parse_subst_string(copy);
 			    noerrs = one;
-			    errflag = oef;
+			    /* Retain any user interrupt error status */
+			    errflag = oef | (errflag & ERRFLAG_INT);
 			    remnulargs(copy);
 			    untokenize(copy);
 			}
@@ -4161,7 +4169,8 @@ modify(char **str, char **ptr)
 			noerrs = 1;
 			parse_subst_string(*str);
 			noerrs = one;
-			errflag = oef;
+			/* Retain any user interrupt error status */
+			errflag = oef | (errflag & ERRFLAG_INT);
 			remnulargs(*str);
 			untokenize(*str);
 		    }
diff --git a/Src/utils.c b/Src/utils.c
index 926814759..d6bb614fa 100644
--- a/Src/utils.c
+++ b/Src/utils.c
@@ -153,7 +153,7 @@ VA_DCL
 
     if (errflag || noerrs) {
 	if (noerrs < 2)
-	    errflag = 1;
+	    errflag |= ERRFLAG_ERROR;
 	return;
     }
 
@@ -161,7 +161,7 @@ VA_DCL
     VA_GET_ARG(ap, fmt, const char *);
     zwarning(NULL, fmt, ap);
     va_end(ap);
-    errflag = 1;
+    errflag |= ERRFLAG_ERROR;
 }
 
 /**/
@@ -181,7 +181,7 @@ VA_DCL
     VA_GET_ARG(ap, fmt, const char *);
     zwarning(cmd, fmt, ap);
     va_end(ap);
-    errflag = 1;
+    errflag |= ERRFLAG_ERROR;
 }
 
 /**/
@@ -330,7 +330,7 @@ zerrmsg(FILE *file, const char *fmt, va_list ap)
 		num = va_arg(ap, int);
 		if (num == EINTR) {
 		    fputs("interrupt\n", file);
-		    errflag = 1;
+		    errflag |= ERRFLAG_ERROR;
 		    return;
 		}
 		errmsg = strerror(num);
diff --git a/Src/zsh.h b/Src/zsh.h
index 031deaf3f..b366e0ff4 100644
--- a/Src/zsh.h
+++ b/Src/zsh.h
@@ -2623,6 +2623,20 @@ enum trap_state {
 #define IN_EVAL_TRAP() \
     (intrap && !trapisfunc && traplocallevel == locallevel)
 
+/*
+ * Bits in the errflag variable.
+ */
+enum errflag_bits {
+    /*
+     * Standard internal error bit.
+     */
+    ERRFLAG_ERROR = 1,
+    /*
+     * User interrupt.
+     */
+    ERRFLAG_INT = 2
+};
+
 /***********/
 /* Sorting */
 /***********/