handy.h: Create nBIT_UMAX() macro

[perl5.git] / sv.h

diff --git a/sv.h b/sv.h
index ebff9f5..2f4a85f 100644 (file)
--- a/sv.h
+++ b/sv.h
@@ -1973,7 +1973,7 @@ Like C<sv_catsv> but doesn't process magic.
                            && SvCUR(sv)+1 < SvLEN(sv))
    /* Note: To allow 256 COW "copies", a refcnt of 0 means 1. */
 #   define CowREFCNT(sv)       (*(U8 *)(SvPVX(sv)+SvLEN(sv)-1))
-#   define SV_COW_REFCNT_MAX   ((1 << sizeof(U8)*8) - 1)
+#   define SV_COW_REFCNT_MAX   nBIT_UMAX(sizeof(U8) * CHARBITS)
 #   define CAN_COW_MASK        (SVf_POK|SVf_ROK|SVp_POK|SVf_FAKE| \
                         SVf_OOK|SVf_BREAK|SVf_READONLY|SVf_PROTECT)
 #endif