Keep LC_NUMERIC in C locale, except for brief periods

This is for XS modules, so they don't have to worry about the radix
being a non-dot.  When the locale needs to be in the underlying one, the
operation should be wrapped using macros for the purpose.  That API may
change as we gain experience in 5.21, so I'm not including it now.

1 files changed, 6 insertions, 0 deletions

diff --git a/locale.c b/locale.c
index b93a821907..efd46fd561 100644
--- a/locale.c
+++ b/locale.c
@@ -180,6 +180,12 @@ Perl_new_numeric(pTHX_ const char *newnum)
     PL_numeric_standard = ((*save_newnum == 'C' && save_newnum[1] == '\0')
                             || strEQ(save_newnum, "POSIX"));
     PL_numeric_local = TRUE;
+
+    /* Keep LC_NUMERIC in the C locale.  This is for XS modules, so they don't
+     * have to worry about the radix being a non-dot.  (Core operations that
+     * need the underlying locale change to it temporarily). */
+    set_numeric_standard();
+
     set_numeric_radix();
 
 #endif /* USE_LOCALE_NUMERIC */