Document limitations in PUSHi et al macros and add new mPUSHi et al macros

Message-ID: <40921749.3050600@uk.radan.com>

p4raw-id: //depot/perl@22756

1 files changed, 96 insertions, 12 deletions

diff --git a/pp.h b/pp.h
index 3893c10d9d..7178ae76c7 100644
--- a/pp.h
+++ b/pp.h
@@ -162,45 +162,117 @@ onto the stack.
 
 =for apidoc Am|void|PUSHs|SV* sv
 Push an SV onto the stack.  The stack must have room for this element.
-Does not handle 'set' magic.  See C<XPUSHs>.
+Does not handle 'set' magic.  Does not use C<TARG>.  See also C<PUSHmortal>,
+C<XPUSHs> and C<XPUSHmortal>.
 
 =for apidoc Am|void|PUSHp|char* str|STRLEN len
 Push a string onto the stack.  The stack must have room for this element.
-The C<len> indicates the length of the string.  Handles 'set' magic.  See
-C<XPUSHp>.
+The C<len> indicates the length of the string.  Handles 'set' magic.  Uses
+C<TARG>, so C<dTARGET> or C<dXSTARG> should be called to declare it.  Do not
+call multiple C<TARG>-oriented macros to return lists from XSUB's - see
+C<mPUSHp> instead.  See also C<XPUSHp> and C<mXPUSHp>.
 
 =for apidoc Am|void|PUSHn|NV nv
 Push a double onto the stack.  The stack must have room for this element.
-Handles 'set' magic.  See C<XPUSHn>.
+Handles 'set' magic.  Uses C<TARG>, so C<dTARGET> or C<dXSTARG> should be
+called to declare it.  Do not call multiple C<TARG>-oriented macros to
+return lists from XSUB's - see C<mPUSHn> instead.  See also C<XPUSHn> and
+C<mXPUSHn>.
 
 =for apidoc Am|void|PUSHi|IV iv
 Push an integer onto the stack.  The stack must have room for this element.
-Handles 'set' magic.  See C<XPUSHi>.
+Handles 'set' magic.  Uses C<TARG>, so C<dTARGET> or C<dXSTARG> should be
+called to declare it.  Do not call multiple C<TARG>-oriented macros to 
+return lists from XSUB's - see C<mPUSHi> instead.  See also C<XPUSHi> and
+C<mXPUSHi>.
 
 =for apidoc Am|void|PUSHu|UV uv
 Push an unsigned integer onto the stack.  The stack must have room for this
-element.  See C<XPUSHu>.
+element.  Handles 'set' magic.  Uses C<TARG>, so C<dTARGET> or C<dXSTARG>
+should be called to declare it.  Do not call multiple C<TARG>-oriented
+macros to return lists from XSUB's - see C<mPUSHu> instead.  See also
+C<XPUSHu> and C<mXPUSHu>.
 
 =for apidoc Am|void|XPUSHs|SV* sv
 Push an SV onto the stack, extending the stack if necessary.  Does not
-handle 'set' magic.  See C<PUSHs>.
+handle 'set' magic.  Does not use C<TARG>.  See also C<XPUSHmortal>,
+C<PUSHs> and C<PUSHmortal>.
 
 =for apidoc Am|void|XPUSHp|char* str|STRLEN len
 Push a string onto the stack, extending the stack if necessary.  The C<len>
-indicates the length of the string.  Handles 'set' magic.  See
-C<PUSHp>.
+indicates the length of the string.  Handles 'set' magic.  Uses C<TARG>, so
+C<dTARGET> or C<dXSTARG> should be called to declare it.  Do not call
+multiple C<TARG>-oriented macros to return lists from XSUB's - see
+C<mXPUSHp> instead.  See also C<PUSHp> and C<mPUSHp>.
 
 =for apidoc Am|void|XPUSHn|NV nv
 Push a double onto the stack, extending the stack if necessary.  Handles
-'set' magic.  See C<PUSHn>.
+'set' magic.  Uses C<TARG>, so C<dTARGET> or C<dXSTARG> should be called to
+declare it.  Do not call multiple C<TARG>-oriented macros to return lists
+from XSUB's - see C<mXPUSHn> instead.  See also C<PUSHn> and C<mPUSHn>.
 
 =for apidoc Am|void|XPUSHi|IV iv
 Push an integer onto the stack, extending the stack if necessary.  Handles
-'set' magic. See C<PUSHi>.
+'set' magic.  Uses C<TARG>, so C<dTARGET> or C<dXSTARG> should be called to
+declare it.  Do not call multiple C<TARG>-oriented macros to return lists
+from XSUB's - see C<mXPUSHi> instead.  See also C<PUSHi> and C<mPUSHi>.
 
 =for apidoc Am|void|XPUSHu|UV uv
 Push an unsigned integer onto the stack, extending the stack if necessary.
-See C<PUSHu>.
+Handles 'set' magic.  Uses C<TARG>, so C<dTARGET> or C<dXSTARG> should be
+called to declare it.  Do not call multiple C<TARG>-oriented macros to
+return lists from XSUB's - see C<mXPUSHu> instead.  See also C<PUSHu> and
+C<mPUSHu>.
+
+=for apidoc Am|void|PUSHmortal
+Push a new mortal SV onto the stack.  The stack must have room for this
+element.  Does not handle 'set' magic.  Does not use C<TARG>.  See also
+C<PUSHs>, C<XPUSHmortal> and C<XPUSHs>.
+
+=for apidoc Am|void|mPUSHp|char* str|STRLEN len
+Push a string onto the stack.  The stack must have room for this element.
+The C<len> indicates the length of the string.  Does not handle 'set' magic.
+Does not use C<TARG>.  See also C<PUSHp>, C<mXPUSHp> and C<XPUSHp>.
+
+=for apidoc Am|void|mPUSHn|NV nv
+Push a double onto the stack.  The stack must have room for this element.
+Does not handle 'set' magic.  Does not use C<TARG>.  See also C<PUSHn>,
+C<mXPUSHn> and C<XPUSHn>.
+
+=for apidoc Am|void|mPUSHi|IV iv
+Push an integer onto the stack.  The stack must have room for this element.
+Does not handle 'set' magic.  Does not use C<TARG>.  See also C<PUSHi>,
+C<mXPUSHi> and C<XPUSHi>.
+
+=for apidoc Am|void|mPUSHu|UV uv
+Push an unsigned integer onto the stack.  The stack must have room for this
+element.  Does not handle 'set' magic.  Does not use C<TARG>.  See also
+C<PUSHu>, C<mXPUSHu> and C<XPUSHu>.
+
+=for apidoc Am|void|XPUSHmortal
+Push a new mortal SV onto the stack, extending the stack if necessary.  Does
+not handle 'set' magic.  Does not use C<TARG>.  See also C<XPUSHs>,
+C<PUSHmortal> and C<PUSHs>.
+
+=for apidoc Am|void|mXPUSHp|char* str|STRLEN len
+Push a string onto the stack, extending the stack if necessary.  The C<len>
+indicates the length of the string.  Does not handle 'set' magic.  Does not
+use C<TARG>.  See also C<XPUSHp>, C<mPUSHp> and C<PUSHp>.
+
+=for apidoc Am|void|mXPUSHn|NV nv
+Push a double onto the stack, extending the stack if necessary.  Does not
+handle 'set' magic.  Does not use C<TARG>.  See also C<XPUSHn>, C<mPUSHn>
+and C<PUSHn>.
+
+=for apidoc Am|void|mXPUSHi|IV iv
+Push an integer onto the stack, extending the stack if necessary.  Does not
+handle 'set' magic.  Does not use C<TARG>.  See also C<XPUSHi>, C<mPUSHi>
+and C<PUSHi>.
+
+=for apidoc Am|void|mXPUSHu|UV uv
+Push an unsigned integer onto the stack, extending the stack if necessary.
+Does not handle 'set' magic.  Does not use C<TARG>.  See also C<XPUSHu>,
+C<mPUSHu> and C<PUSHu>.
 
 =cut
 */
@@ -231,6 +303,18 @@ See C<PUSHu>.
 #define XPUSHu(u)	STMT_START { sv_setuv(TARG, (UV)(u)); XPUSHTARG; } STMT_END
 #define XPUSHundef	STMT_START { SvOK_off(TARG); XPUSHs(TARG); } STMT_END
 
+#define PUSHmortal(s)	PUSHs(sv_newmortal())
+#define mPUSHp(p,l)	STMT_START { sv_setpvn(PUSHmortal, (p), (l)); } STMT_END
+#define mPUSHn(n)	STMT_START { sv_setnv(PUSHmortal, (NV)(n)); } STMT_END
+#define mPUSHi(i)	STMT_START { sv_setiv(PUSHmortal, (IV)(i)); } STMT_END
+#define mPUSHu(u)	STMT_START { sv_setuv(PUSHmortal, (UV)(u)); } STMT_END
+
+#define XPUSHmortal(s)	STMT_START { EXTEND(sp,1); PUSHmortal; } STMT_END
+#define mXPUSHp(p,l)	STMT_START { sv_setpvn(XPUSHmortal, (p), (l)); } STMT_END
+#define mXPUSHn(n)	STMT_START { sv_setnv(XPUSHmortal, (NV)(n)); } STMT_END
+#define mXPUSHi(i)	STMT_START { sv_setiv(XPUSHmortal, (IV)(i)); } STMT_END
+#define mXPUSHu(u)	STMT_START { sv_setuv(XPUSHmortal, (UV)(u)); } STMT_END
+
 #define SETs(s)		(*sp = s)
 #define SETTARG		STMT_START { SvSETMAGIC(TARG); SETs(TARG); } STMT_END
 #define SETp(p,l)	STMT_START { sv_setpvn(TARG, (p), (l)); SETTARG; } STMT_END