Fix SEGV in error message when FNR hasn't been set yet.

2 files changed, 6 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 74c4e89a..9592f48f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2021-10-20         Andrew J. Schorr      <aschorr@telemetry-investments.com>
+
+	* msg.c (err): Need to check that FNR_node->var_value is non-NULL
+	before testing with is_mpg_number.
+
 2021-10-18         Arnold D. Robbins     <arnold@skeeve.com>
 
 	Factor duplicated code out into a separate function.
diff --git a/msg.c b/msg.c
index 0dc3f718..2ec3dfa9 100644
--- a/msg.c
+++ b/msg.c
@@ -78,7 +78,7 @@ err(bool isfatal, const char *s, const char *emsg, va_list argp)
 	}
 
 #ifdef HAVE_MPFR
-	if (FNR_node && is_mpg_number(FNR_node->var_value)) {
+	if (FNR_node && FNR_node->var_value && is_mpg_number(FNR_node->var_value)) {
 		NODE *val;
 		val = mpg_update_var(FNR_node);
 		assert((val->flags & MPZN) != 0);