Re: IBM z/OS compatibility issues - pthread

[Bruno Haible]

Hi Daniel,

> > Can you please do a fresh start on this?
> >   - Create a testdir for module 'pthread-rwlock'.
> >   - Build it with -D_UNIX95_THREADS -D_XOPEN_SOURCE=600.
> 
> That gives me the same compile error as a full build:
> 
> source='/tmp/testdir/gltests/test-pthread.c' object='test-pthread.o' 
> libtool=no \
> DEPDIR=.deps depmode=aix /bin/sh /tmp/testdir/build-aux/depcomp \
> xlc-wrap -DHAVE_CONFIG_H -I. -I/tmp/testdir/gltests -I..  
> -DGNULIB_STRICT_CHECKING=1 -DIN_GNULIB_TESTS=1 -I. -I/tmp/testdir/gltests 
> -I.. -I/tmp/testdir/gltests/.. -I../gllib -I/tmp/testdir/gltests/../gllib 
> -D_UNIX95_THREADS -D_XOPEN_SOURCE=600 -DNSIG=39 -qhaltonmsg=CCN3296  -g -q64 
> -qfloat=ieee -qlanglvl=extc99 -qenumsize=4  -c -o test-pthread.o 
> /tmp/testdir/gltests/test-pthread.c
> ERROR CCN3221 /tmp/testdir/gltests/test-pthread.c:35    Initializer must be a 
> valid constant expression.
> WARNING CCN3196 /tmp/testdir/gltests/test-pthread.c:56    Initialization 
> between types "void*" and "unsigned long" is not allowed.
> CCN0793(I) Compilation failed for file /tmp/testdir/gltests/test-pthread.c.
>   Object file not created.
> make[4]: *** [test-pthread.o] Error 12
> make[4]: Leaving directory `/tmp/gnulib-build/gltests'
> make[3]: *** [all-recursive] Error 1
> make[3]: Leaving directory `/tmp/gnulib-build/gltests'
> make[2]: *** [all] Error 2
> make[2]: Leaving directory `/tmp/gnulib-build/gltests'
> make[1]: *** [all-recursive] Error 1
> make[1]: Leaving directory `/tmp/gnulib-build'
> make: *** [all] Error 2
> 
> Whatever magic exists to work around a missing PTHREAD_RWLOCK_INITIALIZER,
> I'm not seeing it...

Oh, I see now. We do have a workaround for this situation in the 'lock'
module, but not in the 'pthread-rwlock' module.

Since PTHREAD_RWLOCK_INITIALIZER_NP is documented [1], we can use it, as you
suggest.

[1] 
https://www.ibm.com/support/knowledgecenter/cs/SSLTBW_2.2.0/com.ibm.zos.v2r2.bpxbd00/pthrdh.htm


2019-12-21  Bruno Haible  <address@hidden>

        pthread-thread, lock: On z/OS, use PTHREAD_RWLOCK_INITIALIZER_NP.
        Reported by Daniel Richard G. in
        <https://lists.gnu.org/archive/html/bug-gnulib/2019-11/msg00001.html>
        <https://lists.gnu.org/archive/html/bug-gnulib/2019-12/msg00167.html>
        * lib/pthread.in.h (PTHREAD_RWLOCK_INITIALIZER): Define to
        PTHREAD_RWLOCK_INITIALIZER_NP when possible.
        * lib/glthread/lock.h: Allow PTHREAD_RWLOCK_INITIALIZER_NP as an
        alternative to PTHREAD_RWLOCK_INITIALIZER.
        * lib/glthread/lock.c: Likewise.

diff --git a/lib/glthread/lock.c b/lib/glthread/lock.c
index 2537839..9d84090 100644
--- a/lib/glthread/lock.c
+++ b/lib/glthread/lock.c
@@ -254,7 +254,7 @@ glthread_recursive_lock_destroy (gl_recursive_lock_t *lock)
 
 # if HAVE_PTHREAD_RWLOCK && (HAVE_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER || 
(defined PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP && (__GNU_LIBRARY__ 
> 1)))
 
-#  ifdef PTHREAD_RWLOCK_INITIALIZER
+#  if defined PTHREAD_RWLOCK_INITIALIZER || defined 
PTHREAD_RWLOCK_INITIALIZER_NP
 
 #   if !HAVE_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER
      /* glibc with bug https://sourceware.org/bugzilla/show_bug.cgi?id=13701 */
diff --git a/lib/glthread/lock.h b/lib/glthread/lock.h
index ffbec15..890c459 100644
--- a/lib/glthread/lock.h
+++ b/lib/glthread/lock.h
@@ -308,7 +308,7 @@ typedef pthread_mutex_t gl_lock_t;
 
 # if HAVE_PTHREAD_RWLOCK && (HAVE_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER || 
(defined PTHREAD_RWLOCK_WRITER_NONRECURSIVE_INITIALIZER_NP && (__GNU_LIBRARY__ 
> 1)))
 
-#  ifdef PTHREAD_RWLOCK_INITIALIZER
+#  if defined PTHREAD_RWLOCK_INITIALIZER || defined 
PTHREAD_RWLOCK_INITIALIZER_NP
 
 typedef pthread_rwlock_t gl_rwlock_t;
 #   define gl_rwlock_define(STORAGECLASS, NAME) \
@@ -316,8 +316,13 @@ typedef pthread_rwlock_t gl_rwlock_t;
 #   define gl_rwlock_define_initialized(STORAGECLASS, NAME) \
       STORAGECLASS pthread_rwlock_t NAME = gl_rwlock_initializer;
 #   if HAVE_PTHREAD_RWLOCK_RDLOCK_PREFER_WRITER
-#    define gl_rwlock_initializer \
-       PTHREAD_RWLOCK_INITIALIZER
+#    if defined PTHREAD_RWLOCK_INITIALIZER
+#     define gl_rwlock_initializer \
+        PTHREAD_RWLOCK_INITIALIZER
+#    else
+#     define gl_rwlock_initializer \
+        PTHREAD_RWLOCK_INITIALIZER_NP
+#    endif
 #    define glthread_rwlock_init(LOCK) \
        (pthread_in_use () ? pthread_rwlock_init (LOCK, NULL) : 0)
 #   else /* glibc with bug 
https://sourceware.org/bugzilla/show_bug.cgi?id=13701 */
diff --git a/lib/pthread.in.h b/lib/pthread.in.h
index a6fb3d9..1baa938 100644
--- a/lib/pthread.in.h
+++ b/lib/pthread.in.h
@@ -281,7 +281,11 @@ typedef unsigned int pthread_rwlockattr_t;
 # define PTHREAD_RWLOCK_INITIALIZER \
    { PTHREAD_MUTEX_INITIALIZER, PTHREAD_COND_INITIALIZER, 
PTHREAD_COND_INITIALIZER, 0, 0 }
 #else
-# if !@HAVE_PTHREAD_T@
+# if @HAVE_PTHREAD_T@
+#  if !defined PTHREAD_RWLOCK_INITIALIZER && defined 
PTHREAD_RWLOCK_INITIALIZER_NP /* z/OS */
+#   define PTHREAD_RWLOCK_INITIALIZER PTHREAD_RWLOCK_INITIALIZER_NP
+#  endif
+# else
 #  if !GNULIB_defined_pthread_rwlock_types
 typedef int pthread_rwlock_t;
 typedef unsigned int pthread_rwlockattr_t;