sv.h - add SvREFCNT_dec_set_NULL()

and also SvREFCNT_dec_ret_NULL() which is used to implement
SvREFCNT_dec_set_NULL(). The set_NULL() macro is intended to
be used to replace code like this:

    if (sv) {
        SvREFCNT_dec_NN(sv);
        sv = NULL;
    }

The function form just facilitates it, and can be used in situations
where returning NULL after decrementing a refcount would be reduce
code complexity.

1 files changed, 12 insertions, 0 deletions

diff --git a/sv_inline.h b/sv_inline.h
index 1bb8c2897d..3adc130575 100644
--- a/sv_inline.h
+++ b/sv_inline.h
@@ -664,6 +664,7 @@ Perl_SvREFCNT_inc(SV *sv)
         SvREFCNT(sv)++;
     return sv;
 }
+
 PERL_STATIC_INLINE SV *
 Perl_SvREFCNT_inc_NN(SV *sv)
 {
@@ -672,12 +673,14 @@ Perl_SvREFCNT_inc_NN(SV *sv)
     SvREFCNT(sv)++;
     return sv;
 }
+
 PERL_STATIC_INLINE void
 Perl_SvREFCNT_inc_void(SV *sv)
 {
     if (LIKELY(sv != NULL))
         SvREFCNT(sv)++;
 }
+
 PERL_STATIC_INLINE void
 Perl_SvREFCNT_dec(pTHX_ SV *sv)
 {
@@ -690,6 +693,15 @@ Perl_SvREFCNT_dec(pTHX_ SV *sv)
     }
 }
 
+PERL_STATIC_INLINE SV *
+Perl_SvREFCNT_dec_ret_NULL(pTHX_ SV *sv)
+{
+    PERL_ARGS_ASSERT_SVREFCNT_DEC_RET_NULL;
+    Perl_SvREFCNT_dec(aTHX_ sv);
+    return NULL;
+}
+
+
 PERL_STATIC_INLINE void
 Perl_SvREFCNT_dec_NN(pTHX_ SV *sv)
 {