util.c: Add comment

[perl5.git] / sv.h

diff --git a/sv.h b/sv.h
index dcd53f7..48b05ec 100644 (file)
--- a/sv.h
+++ b/sv.h
@@ -482,6 +482,7 @@ struct xpvlv {
     SV*                xlv_targ;
     char       xlv_type;       /* k=keys .=pos x=substr v=vec /=join/re
                                 * y=alem/helem/iter t=tie T=tied HE */
+    char       xlv_flags;      /* 1 = negative offset  2 = negative len */
 };
 
 /* This structure works in 3 ways - regular scalar, GV with GP, or fast
@@ -848,6 +849,7 @@ in gv.h: */
                                 ? mg_find(sv,PERL_MAGIC_vstring) : NULL)
 
 #define SvOOK(sv)              (SvFLAGS(sv) & SVf_OOK)
+#define SvOOK_on(sv)           (SvFLAGS(sv) |= SVf_OOK)
 #define SvOOK_off(sv)          ((void)(SvOOK(sv) && sv_backoff(sv)))
 
 #define SvFAKE(sv)             (SvFLAGS(sv) & SVf_FAKE)
@@ -1324,6 +1326,7 @@ the scalar's value cannot change unless written to.
 #define LvTARG(sv)     ((XPVLV*)  SvANY(sv))->xlv_targ
 #define LvTARGOFF(sv)  ((XPVLV*)  SvANY(sv))->xlv_targoff
 #define LvTARGLEN(sv)  ((XPVLV*)  SvANY(sv))->xlv_targlen
+#define LvFLAGS(sv)    ((XPVLV*)  SvANY(sv))->xlv_flags
 
 #define IoIFP(sv)      (sv)->sv_u.svu_fp
 #define IoOFP(sv)      ((XPVIO*)  SvANY(sv))->xio_ofp
@@ -1414,7 +1417,7 @@ C<SvPVx> for a version which guarantees to evaluate sv only once.
 =for apidoc Am|char*|SvPVx|SV* sv|STRLEN len
 A version of C<SvPV> which guarantees to evaluate C<sv> only once.
 Only use this if C<sv> is an expression with side effects, otherwise use the
-more efficient C<SvPVX>.
+more efficient C<SvPV>.
 
 =for apidoc Am|char*|SvPV_nomg|SV* sv|STRLEN len
 Like C<SvPV> but doesn't process magic.