When strtod sets errno, force the numeric value to zero.

2 files changed, 19 insertions, 3 deletions

diff --git a/ChangeLog b/ChangeLog
index fcf646a0..0fa04f6d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2015-04-16         Andrew J. Schorr     <aschorr@telemetry-investments.com>
+
+	* node.c (r_force_number): If strtod sets errno, then force the
+	numeric value in node->numbr to zero. For subnormal values, strtod
+	sets errno but does not return zero, and we don't want to retain
+	those subnormal values.
+
 2015-04-16         Arnold D. Robbins     <arnold@skeeve.com>
 
 	* builtin.c (do_strftime): Use a double for the timestamp and
diff --git a/node.c b/node.c
index f19354e6..1741a13b 100644
--- a/node.c
+++ b/node.c
@@ -138,11 +138,20 @@ r_force_number(NODE *n)
 		ptr++;
 	*cpend = save;
 finish:
-	if (errno == 0 && ptr == cpend) {
-		n->flags |= newflags;
-		n->flags |= NUMCUR;
+	if (errno == 0) {
+		if (ptr == cpend) {
+			n->flags |= newflags;
+			n->flags |= NUMCUR;
+		}
+		/* else keep the leading numeric value without updating flags */
 	} else {
 		errno = 0;
+		/*
+		 * N.B. For subnormal values, strtod may return the
+		 * floating-point representation while setting errno to ERANGE.
+		 * We force the numeric value to 0 in such cases.
+		 */
+		n->numbr = 0;
 	}
 
 	return n;