diff --git a/Lib/perl5/perlprimtypes.swg b/Lib/perl5/perlprimtypes.swg
index f2a614030..86a78c5bf 100644
--- a/Lib/perl5/perlprimtypes.swg
+++ b/Lib/perl5/perlprimtypes.swg
@@ -311,8 +311,9 @@ SWIG_AsVal_dec(double)(SV *obj, double *val)
     const char *nptr = SvPV_nolen(obj);
     if (nptr) {
       char *endptr;
+      double v;
       errno = 0;
-      double v = strtod(nptr, &endptr);
+      v = strtod(nptr, &endptr);
       if (errno == ERANGE) {
 	errno = 0;
 	return SWIG_OverflowError;