Avoid and document a weird bug in UNICOS/mk.

p4raw-id: //depot/perl@15527

diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index 7589276..bb938cf 100644 (file)
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -2688,13 +2688,17 @@ threads are considered fundamentally broken.
 
 =head2 UNICOS and UNICOS/mk
 
-The io/fs test #31 is failing because in UNICOS and UNICOS/mk
-truncate() cannot be used to grow the size of filehandles, only
-to reduce the size.  The workaround is to truncate files instead
-of filehandles.
+The io/fs test #31 is failing because in UNICOS and UNICOS/mk the Perl
+truncate() cannot be used to grow the size of filehandles, only to
+reduce the size.  The workaround is to truncate files instead of
+filehandles.
 
 =head2 UNICOS/mk
 
+=over 4
+
+=item *
+
 During Configure the test
 
     Guessing which symbols your C compiler and preprocessor define...
@@ -2718,6 +2722,16 @@ from Perl the constants defined using C preprocessor, cpp.  Because of
 the above error parts of the converted headers will be invisible.
 Luckily, these days the need for h2ph is rare.
 
+=item *
+
+If building Perl with the interpreter threads (ithreads), the
+getgrent(), getgrnam(), and getgrgid() functions cannot return the
+list of the group members due to a bug in the multithreaded support of
+UNICOS/mk.  What this means that in list context the functions will
+return only three values, not four.
+
+=back
+
 =head2 UTS
 
 There are a few known test failures, see L<perluts>.

diff --git a/pp_sys.c b/pp_sys.c
index 827d8f6..2361b3c 100644 (file)
--- a/pp_sys.c
+++ b/pp_sys.c
@@ -5430,12 +5430,22 @@ PP(pp_ggrent)
        PUSHs(sv = sv_mortalcopy(&PL_sv_no));
        sv_setiv(sv, (IV)grent->gr_gid);
 
+#if !(defined(_CRAYMPP) && defined(USE_REENTRANT_API)
        PUSHs(sv = sv_mortalcopy(&PL_sv_no));
+       /* In UNICOS/mk (_CRAYMPP) the multithreading
+        * versions (getgrnam_r, getgrgid_r)
+        * seem to return an illegal pointer
+        * as the group members list, gr_mem.
+        * getgrent() doesn't even have a _r version
+        * but the gr_mem is poisonous anyway.
+        * So yes, you cannot get the list of group
+        * members if building multithreaded in UNICOS/mk. */
        for (elem = grent->gr_mem; elem && *elem; elem++) {
            sv_catpv(sv, *elem);
            if (elem[1])
                sv_catpvn(sv, " ", 1);
        }
+#endif
     }
 
     RETURN;