Re: Build breakage due to missing semaphore.h on z/OS

[Bruno Haible]

Hi Daniel,

> Building current Git on z/OS fails with
> 
> source='/u/username/testdir/gltests/test-lock.c' object='test-lock.o' 
> libtool=no \
> DEPDIR=.deps depmode=aix /bin/sh /u/username/testdir/build-aux/depcomp \
> xlc-wrap -DHAVE_CONFIG_H -DEXEEXT=\"\" -I. -I/u/username/testdir/gltests -I.. 
>  -DGNULIB_STRICT_CHECKING=1 -DIN_GNULIB_TESTS=1 -I. 
> -I/u/username/testdir/gltests -I.. -I/u/username/testdir/gltests/.. 
> -I../gllib -I/u/username/testdir/gltests/../gllib -D_XOPEN_SOURCE=600 
> -DNSIG=39 -qhaltonmsg=CCN3296  -g -qfloat=ieee -qlanglvl=extc99  -c -o 
> test-lock.o /u/username/testdir/gltests/test-lock.c
> ERROR CCN3296 /u/username/testdir/gltests/test-lock.c:110   #include file 
> <semaphore.h> not found.
> ERROR CCN3046 /u/username/testdir/gltests/test-lock.c:147   Syntax error.
> ERROR CCN3278 /u/username/testdir/gltests/test-lock.c:148   The structure 
> definition must specify a member list.
> [...]
> 
> 
> The problem may be found in test-lock.c:
> 
>     #if USE_POSIX_THREADS
>     /* Whether to use a semaphore to communicate information between threads.
>        If set to 0, a lock is used. If set to 1, a semaphore is used.
>        Uncomment this to reduce the dependencies of this test.  */
>     # define USE_SEMAPHORE 1
>     #endif
> 
>     ...
> 
>     #include "glthread/thread.h"
>     #include "glthread/yield.h"
>     #if USE_SEMAPHORE
>     # include <errno.h>
>     # include <semaphore.h>
>     #endif
> 
> $ ls /usr/include/semaphore.h
> ls: FSUM6785 File or directory "/usr/include/semaphore.h" is not found
> 
> z/OS has POSIX threads (and pthread.h), but there is no semaphore.h
> header. The sem_*() functions do not appear to exist on this platform.
> 
> I worked around this with a quick-and-dirty "#if defined(__MVS__)", but
> a better fix may be to use HAVE_SEMAPHORE_H.

Thanks for the report and explanations. The following patch should fix it.
Pushed.


2017-02-20  Bruno Haible  <address@hidden>

        lock tests: Fix build failure on z/OS.
        Reported by Daniel Richard G. <address@hidden>.
        * modules/lock-tests (configure.ac): Test for <semaphore.h>.
        * tests/test-lock.c (USE_SEMAPHORE): Don't set if <semaphore.h> does not
        exist.

diff --git a/modules/lock-tests b/modules/lock-tests
index b7f1a73..bfab1f4 100644
--- a/modules/lock-tests
+++ b/modules/lock-tests
@@ -8,6 +8,7 @@ usleep
 yield
 
 configure.ac:
+AC_CHECK_HEADERS_ONCE([semaphore.h])
 
 Makefile.am:
 TESTS += test-rwlock1 test-lock
diff --git a/tests/test-lock.c b/tests/test-lock.c
index f3da4cc..c6bc399 100644
--- a/tests/test-lock.c
+++ b/tests/test-lock.c
@@ -58,7 +58,7 @@
    synchronization/communication between different CPUs.  */
 #define USE_VOLATILE 0
 
-#if USE_POSIX_THREADS
+#if USE_POSIX_THREADS && HAVE_SEMAPHORE_H
 /* Whether to use a semaphore to communicate information between threads.
    If set to 0, a lock is used. If set to 1, a semaphore is used.
    Uncomment this to reduce the dependencies of this test.  */