enable propagating exception objects via Perl_croak() in XS code

(from Gisle Aas)

p4raw-id: //depot/perl@6125

diff --git a/util.c b/util.c
index 8d6ecad..74b374c 100644 (file)
--- a/util.c
+++ b/util.c
@@ -1580,14 +1580,20 @@ Perl_vcroak(pTHX_ const char* pat, va_list *args)
     SV *msv;
     STRLEN msglen;
 
-    msv = vmess(pat, args);
-    if (PL_errors && SvCUR(PL_errors)) {
-       sv_catsv(PL_errors, msv);
-       message = SvPV(PL_errors, msglen);
-       SvCUR_set(PL_errors, 0);
+    if (pat) {
+       msv = vmess(pat, args);
+       if (PL_errors && SvCUR(PL_errors)) {
+           sv_catsv(PL_errors, msv);
+           message = SvPV(PL_errors, msglen);
+           SvCUR_set(PL_errors, 0);
+       }
+       else
+           message = SvPV(msv,msglen);
+    }
+    else {
+       message = Nullch;
+       msglen = 0;
     }
-    else
-       message = SvPV(msv,msglen);
 
     DEBUG_S(PerlIO_printf(Perl_debug_log, "croak: 0x%"UVxf" %s",
                          PTR2UV(thr), message));
@@ -1606,9 +1612,14 @@ Perl_vcroak(pTHX_ const char* pat, va_list *args)
 
            ENTER;
            save_re_context();
-           msg = newSVpvn(message, msglen);
-           SvREADONLY_on(msg);
-           SAVEFREESV(msg);
+           if (message) {
+               msg = newSVpvn(message, msglen);
+               SvREADONLY_on(msg);
+               SAVEFREESV(msg);
+           }
+           else {
+               msg = ERRSV;
+           }
 
            PUSHSTACKi(PERLSI_DIEHOOK);
            PUSHMARK(SP);
@@ -1655,9 +1666,16 @@ Perl_croak_nocontext(const char *pat, ...)
 /*
 =for apidoc croak
 
-This is the XSUB-writer's interface to Perl's C<die> function.  Use this
-function the same way you use the C C<printf> function.  See
-C<warn>.
+This is the XSUB-writer's interface to Perl's C<die> function.
+Normally use this function the same way you use the C C<printf>
+function.  See C<warn>.
+
+If you want to throw an exception object, assign the object to
+C<$@> and then pass C<Nullch> to croak():
+
+   errsv = get_sv("@", TRUE);
+   sv_setsv(errsv, exception_object);
+   croak(Nullch);
 
 =cut
 */